The Way Forward in Quantifying Extended Exergy

energies Article

The Way Forward in Quantifying Extended Exergy Efficiency Ricardo Manso *, Tânia Sousa

and Tiago Domingos

MARETEC—Marine, Environment and Technology Centre, Department of Mechanical Engineering, Instituto Superior Technical, University of Lisbon, 1049-001 Lisbon, Portugal; [email protected] (T.S.); [email protected] (T.D.) * Correspondence: [email protected]; Tel.: +351-968972498 Received: 28 June 2018; Accepted: 18 September 2018; Published: 21 September 2018







Abstract: Extended exergy accounting (EEA) is a methodology which estimates the extended exergy cost (EEC) of a product or a service or the extended exergy efficiency (EEE) of a country or economic sector taking into account materials, energy, labour, capital, and environmental impact. The use of EEA results for policy or planning purposes has been hampered by: (1) the lack of data to quantify the EEC of most of the inputs, making it almost impossible to quantify the EEC of a product or service and (2) the lack of a conceptual framework to quantify in a consistent way the exergy of labour and capital. In this paper, we make a review of past studies to identify, synthesize, and discuss the different EEA methods. We identified 3 different EEA methods, that we further compare using the Portuguese Agriculture, Forestry, and Fishery (AFF) sector from 2000 to 2012. The equivalent exergies of labour and capital estimated for the AFF sector vary widely among the three EEA methodologies. We propose and test a new EEA methodology to estimate EEE which accounts for these fluxes in a more restricted scope but more consistently and that includes the Environmental Benefit (EB) that represents the capability of the forestry to capture carbon dioxide. Results show that the EEE of the Portuguese AFF sector has increased by 32% from 2000 to 2012. Keywords: exergy; extended exergy accounting; efficiency; environmental assessment; agriculture

1. Introduction The rapid depletion of the natural environment and the will to ensure the survival of present and future generations led mankind to study and address new ways to improve the efficiency of using earth finite resources. Thermodynamic concepts widely adopted to measure the efficiency of industrial processes are being increasingly used to assess the efficiency and sustainability of other societal processes at different scales. Acknowledging that our societal relation with the global environment is above all made through physical interactions, the thermodynamic concept that is better able to measure the quality of these interactions is exergy. In contrast to energy, which is subject to a conservation law and suitable for quantity measurements, exergy is destroyed in any real interaction process, due to irreversibilities, and is absent from conservation principles. Exergy content in a stream or in a system is an entropy free form of energy that measures the work content or the ability to produce work from that stream or system [1]. By aggregating the energy of different flows entering and leaving a system, the energetic assessment of the system tells only a partial story since the quality of such flows is not taken into account. On contrast, exergetic assessments measure all flows by taking into account their quantity and quality. Exergetic analysis of nations, or very large complex systems, began with Reistad [2] who published an exergetic analysis for the US in 1975, using the Energy Resources Exergy Accounting (EREA) approach. Wall [3] made an exergetic analysis for Swedish society in 1980, using the Natural Resources Energies 2018, 11, 2522; doi:10.3390/en11102522

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Exergy Accounting (NREA) methodology which extends the EREA by adding the exergetic content of natural resources and material flows. These exergetic analyses quantified only the intrinsic exergy (physical and chemical exergy) of flows. In 1987, the concept of cumulative Exergy Consumption (CExC), that quantifies the exergy of a stream as the sum of all necessary exergy to bring the stream to the specified state, was introduced by Szargut [4]. CExC was an innovative and important tool that can be used in manufacturing processes, to indicate in each step, the embodied exergy of materials and energy of inflow and outflow fluxes, highlighting the processes were most exergy destruction occurs. It also cumulatively quantifies the necessary exergy to manufacture a desired product, allowing for comparisons between different manufacturing processes and for the quantification of the impact of measures such as recycling or changes in raw materials. The Extended Exergy Accounting (EEA) methodology quantifies additionally three immaterial streams, labour, capital and environmental impact [5] in exergy units. Sciubba [6] argued that the exergetic content assigned to input and output flows in EEA should be the embodied or cumulative, defined as the sum of its physical and chemical exergies plus all net exergies received directly or indirectly in its transformation path including all labour, capital, and environmental costs necessary along each step of the path. In its essence, on top of all energetic and physical fluxes, EEA also accounts three immaterial streams: labour, capital, and environmental remediation or avoidance exergy cost (Figure 1) to quantify the Extended Exergy Cost (EEC) of a stream. Ultimately, all material and energy streams are valued by their EEC from extraction to consumption. The resources or energy carriers which are extracted or collected from the environment are primarily valued by their intrinsic exergy and subsequently attributed an EEC when entering a new transformation process. The EEC measures the overall societal exergy necessary to produce a product or a service. Conceptually, this result is extremely useful since we may identify the products or services with lower EEC or energy carriers with better intrinsic exergy to EEC ratio. The EEC of fluxes is useful in identifying which output environmental fluxes would need more exergy to become non-polluting and the trade-offs in exergy terms between labour, capital, and mass/energy flows. While some of the studies developed using the EEA methodology have the aim of evaluating the EEC of a product or a service [7,8], others focus on quantifying the societal efficiency of a process [9–11]. This extended exergy efficiency (EEE), measured by the ratio between the exergy of the output fluxes and the exergy in the inputs, can have different meanings. If inputs are valued by their EEC, then the efficiency evaluates the performance of all labour, capital, and environmental impacts and of every material and energy carrier used up from extraction to the multiple transformation processes that lead to the intended output flow. In contrast, if inputs are valued by their intrinsic exergies, the efficiency refers solely to the specific transformation process under analysis. EEA societal studies don’t usually refer exergy losses or destruction in their analysis except Ertesvag [9] which includes them in his input-output tables. However, the EEA faces some challenges/difficulties. The first challenge is complexity. EEA is extremely complex if done properly. Take electricity as an example, which is used in almost every device or transformation process. The consumption matrix of the conversion sector is vast and if most of the initial carriers are imported, then the tracking of all interactions is easily lost [12]. The second challenge is the difficulty in developing a useful database for EEC values. The values obtained using the CExC methodology [4] should not be used as EEC because they only take into account energy and material flows. Thus, the EEA methodology implies the use of EEC values obtained by EEA studies in each step of the process. Additionally, the use of upstream EEC values from other publications is problematic unless they were estimated for the same region and year since labour and capital are geographically and time dependent. The third challenge is the difficulty in ensuring consistency when applying the EEA approach. The lack of a solid EEC database led some EEA studies to use an inconsistent approach. Most studies use the intrinsic exergy content of all material and energy flows combined with a cumulative equivalent exergy for capital and labour fluxes. This inconsistency also extends to the environmental impact

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externality which is mainly accounted by pollutants’ intrinsic exergy or by the equivalent exergy of the capital spent in trash and discharge fluxes. These inconsistencies led to EEA results where the equivalent exergies of capital and labour are the dominant flows by a large factor. This disparity between the exergy of different flows is shown in Manso et al. [13], where the results obtained by the EEA approach, using as a case study the Agriculture, Forestry, and Fishing (AFF) economic sector of Portugal from 2000 to 2012, are completely dominated by the exergies of capital and environmental impacts. The fourth challenge is the overestimation of the EEC of a product or service because of double-counting associated with labour. This is well explained by Szargut et al. [14] that shows that accounting for the exergy of labour makes the sum of the EEC of all final useful products higher than the primary exergy used by society. The all-embracing nature of EEA that accounts all major production factors into a transformation process is relevant for sustainability and efficiency studies. However, due to the issues already mentioned: (1) the lack of consistency in accounting for the EEC among flows, (2) the double-counting and arbitrariness in accounting for labour and capital and (3) the lack of an EEC database, its use is problematic. These issues have to be addressed in order to improve the usefulness of EEA for policy purposes. In this paper, we review past studies to identify, synthesize, and discuss the different methods used to quantify exergy with a special focus on the three immaterial production factors of EEA (labour, capital, and environmental impact) and compare the several EEA methodologies using the Agriculture, Forestry and Fishing (AFF) economic sector of Portugal from 2000 to 2012 as a case study, with the aim of providing understanding and clarity for EEA practitioners. The case study and initial dataset is the same used in Manso et al. [13], but here it is used to compare the multiple EEA methodologies while in Manso et al. [13], it was used to compare the exergy efficiency obtained using the EREA, NREA, and one of the EEA approaches. Additionally, this paper addresses the challenge of improving the estimation of EEA externalities, labour, capital, and environmental impacts for sectorial studies. Based on our review, we propose an Intrinsic Extended Exergy Accounting (IEEA) approach to estimate the Extended Exergy Efficiency (EEE) of products/services or sectors that (1) values labour and capital flows more consistently and (2) does not need an EEC database. 2. EEA Methodologies: Review and Synthesis Literature reviews on exergy accounting of nations have already been made by Utlu and Hepbasli [15] and Sousa et al. [16]. Among the studies collected by these reviews, only one applies the Extended Exergy Accounting (EEA) methodology [9]. In this paper, we focus only on EEA studies that either discuss methodological issues or apply EEA to nations or societal economic sectors. Table 1 highlights the analogies and differences between the methodologies used in published EEA studies focusing on (1) the use of intrinsic or cumulative exergy data in their analysis, (2) the methodology applied to labour, capital, and environmental impact and (3) the exergetic evaluation of the outputs. 2.1. Input and Output Exergies for Material and Energy Flows EEA theory defends a cumulative approach to all streams that enter a transformation process to find the EEC of the output streams. From the studies presented in Table 1 we would like to highlight the studies by Ptasinski et al. [17] which used the EcoChem software to translate chemical exergy to CExC and Rocco et al. [18] which used the Ecoinvent database [19] to compute their inputs. No study was able to include inputs with their extended exergy cost and few studies were able to offer extended exergy cost values to a database for EEA use, despite its low utility for studies on other regions or years. Examples include the environmental remediation cost values of carbon monoxide, mono-nitrogen oxides, and sulphur dioxide published by Dai et al. [20] and from carbon dioxide, nitrous oxide, and methane by Seckin et al. [21]. The extended exergy cost values of municipal wastewater and sludge abatement are also known for Turkey in 2006 [8].

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nitrous2018, oxide, and Energies 11, 2522

methane by Seckin et al. [21]. The extended exergy cost values of municipal 4 of 32 wastewater and sludge abatement are also known for Turkey in 2006 [8]. When assessing the efficiency of an economic sector, many authors opted to evaluate their input When assessing the efficiency of anfor economic sector, many authors opted evaluate their flows by their intrinsic exergy, even fluxes leaving a sector to enter thetofollowing. The input main flows by their intrinsic exergy, even for fluxes leaving a sector to enter the following. The main proposal proposal was to quantify the sector’s performance and if cumulative data was introduced, the was to quantify the sector’s performance and if cumulative data was introduced, the efficiency would efficiency would reflect the cumulative performance of all sectors that transformed the flows under reflect the(Figure cumulative performance of all sectors thatinitially transformed the flows under analysis (Figure 1). analysis 1). The EEA approach was not designed to measure efficiencies at the The EEA approach was not initially designed to measure efficiencies at the middle of the transformation middle of the transformation chain, but to ascertain the final cumulative resource and societal chain, but consumption. to ascertain theWhen final cumulative exergetic consumption. the aim exergetic the aim is toresource estimateand thesocietal efficiency, the correct approachWhen is to quantify is to estimate the efficiency, the correct approach is to quantify the input, including only the intrinsic the input, including only the intrinsic or physical and chemical exergies. This modified Extended or physical and chemical exergies. modified Extended Exergy Exergy Analysis methodology wasThis used by Ertesvag [9], Milia andAnalysis Sciubba methodology [22], Sciubba was et al.used [23], by Ertesvag [9], Milia and Sciubba [22], Sciubba et al. [23], Gasparatos et al. [10], Chen and Chen [24], Gasparatos et al. [10], Chen and Chen [24], Bligh and Ugursal [25], and by Seckin et al. [11] for Bligh andand Ugursal [25], fluxes and by(Table Seckin1).et al. [11] for material and energetic fluxes (Table 1). material energetic

. Figure Figure 1. 1. Upstream Upstream systems systems included included in in the the EEA EEA methodology. methodology.

2.2. Labour 2.2. Labour Human labour is an essential production factor in any conversion system, and although not a Human labour is an essential production factor in any conversion system, and although not a novelty in energetic assessments, its correct introduction is controversial [26]. novelty in energetic assessments, its correct introduction is controversial [26]. Sciubba [6] estimated the equivalent exergy of labour (EL ) as the total exergy input to society (Ein ) Sciubba [6] estimated the equivalent exergy of labour (𝐸 ) as the total exergy input to society and the specific exergy of labour (ee L ) as the labour exergy per working hour (Table 1). The exergetic (𝐸 ) and the specific exergy of labour (𝑒𝑒 ) as the labour exergy per working hour (Table 1). The input into the economy of a region in a given year is taken from the environment as resources exergetic input into the economy of a region in a given year is taken from the environment as (natural, renewable, or non-renewable) that travel a partial or complete route along primary sectors, resources (natural, renewable, or non-renewable) that travel a partial or complete route along to manufacturing, and finally to tertiary and domestic. Some resources and products are exchanged primary sectors, to manufacturing, and finally to tertiary and domestic. Some resources and with other countries, where the total exergy Ein is the result of all environmental inputs plus imports products are exchanged with other countries, where the total exergy 𝐸 is the result of all and less exports (Appendix B). This exergetic input sustains all metabolic necessities, all generation of environmental inputs plus imports and less exports (Appendix B). This exergetic input sustains all labour, all manufacturing and transportation abilities, as well as all recreational and leisure activities. metabolic necessities, all generation of labour, all manufacturing and transportation abilities, as well By assuming EL = Ein , the author assumes that all gathered exergy Ein is used to fuel labour. as all recreational and leisure activities. But, labour itself is only one of the outputs of Ein and this creates a major problem when assessing the By assuming 𝐸 = 𝐸 , the author assumes that all gathered exergy 𝐸 is used to fuel labour. domestic sector. Ertesvag [9], Gasparatos et al. [10], Chen and Chen [24], and Bligh and Ugursal [25] But, labour itself is only one of the outputs of 𝐸 and this creates a major problem when assessing followed this methodology and found efficiencies higher than 100% for the domestic sector. the domestic sector. Ertesvag [9], Gasparatos et al. [10], Chen and Chen [24], and Bligh and Ugursal Ptasinski et al. [17] studying the Dutch energy sector, based on EEA, proposed a different labour [25] followed this methodology and found efficiencies higher than 100% for the domestic sector. methodology. The study adds three components, a man-power equivalent exergy (EL,W ) which was Ptasinski et al. [17] studying the Dutch energy sector, based on EEA, proposed a different 300 GJ a year per person (which represents the total exergy inflow per capita for Sweden in 1975 [27]), labour methodology. The study adds three components, a man-power equivalent exergy (𝐸 , ) a skill component (EL,Skill ) comprising compensation of employees (gross wages and salaries) and which was 300 GJ a year per person (which represents the total exergy inflow per capita for Sweden a social component based on the monetary flows of social cost accounts (EL,SA ). The man-power in 1975 [27]), a skill component (𝐸 , ) comprising compensation of employees (gross wages and contribution was almost negligible, while the monetary values of skills and social accounts, converted salaries) and a social component based on the monetary flows of social cost accounts (𝐸 , ). The to exergy by a capital conversion factor, represented respectively around 90% and 10% of EL that man-power contribution was almost negligible, while the monetary values of skills and social varied between 153 MJ/h for central electricity production and 501 MJ/h for refineries. Such different accounts, converted to exergy by a capital conversion factor, represented respectively around 90% values of equivalent labour exergy factors (over three times more), on two branches of the energy and 10% of 𝐸 that varied between 153 MJ/h for central electricity production and 501 MJ/h for sector, result from directly relating labour exergy with wages. refineries. Such different values of equivalent labour exergy factors (over three times more), on two Agricultural sustainability for OECD countries was studied by Hoang and Alauddin [28] in a branches of the energy sector, result from directly relating labour exergy with wages. combination of EEA and cumulative exergy extraction from the natural environment (CEENE) [29] Agricultural sustainability for OECD countries was studied by Hoang and Alauddin [28] in a from 1990 to 2003. In their analysis, the equivalent exergy of labour was accounted as EL = Fe · Nw ttwt , combination of EEA and cumulative exergy extraction from the natural environment (CEENE) [29] where Fe is the daily metabolizable food energy per worker, Nw is the number of workers in the sector

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and tw /tt is the fraction of daily time spent working. The equivalent exergy of labour represented 0.25% off all inputs in the agricultural sector. In contrast to previous studies where the labour exergy flux depends on the lifestyle of a population or wages, the authors assumed that the equivalent exergy of labour was the energy obtained from food, by the workers in the sector, needed to fuel metabolism, during working hours. However, the authors also assume that all hours in a day are fueled by the same number of calories, regardless of whether the person is working or resting. Aware of the imbalance of the domestic sector caused by the methodology that he proposed for labour, Sciubba [30] reviewed the calculation of both capital and labour fluxes. A postulate for labour was created that states that only a fraction, α, of all the incoming exergy Ein is used to support the workers: EL = αEin or ee L = αEin /nworkhours . To obtain α, Sciubba [30] introduced the following equation for the equivalent exergy of labour EL = f · esurv · Np that takes into account the population (Np ), the minimum exergy (esurv ) required to maintain healthy metabolic needs (2500 Kcal/day per person or 1.05 × 107 J/day·person) and f is an enlargement factor that describes the societal exergy needs over the survival mode. To measure the societal amplification factor (f), the author opted to correlate it with the Human Development Index (HDI) [31] where f = HDI/HDI0 being HDI0 the Human Development Index of a pre-industrial society (HDI0 ≈ 0.055). By proposing this equation, Sciubba asserts that the embodied exergy into labour is linearly dependent on HDI, which is the geometric mean of three dimensions: life expectancy and healthy life, knowledge and education, and standard of living and national income [31]. In contrast to the first methodology, where all exergy that entered society was attributed to the labour flux, the new methodology relates both quantities by a factor (α). Figure 2 relates each country’s, Ein∗ , with EL predicted by HDI, for 121 countries. The value for Ein∗ is estimated only with the energy obtained from the International Energy Agency [40]. This accounts only for energy carriers and it is not the total energy that enters a specific country Ein ; it misses the extraction of non-energy carriers, the production from the agricultural sector and their energetic balance of imports minus exports. Thus, Ein is higher than Ein∗ . Also, the energy carriers are valued by their energetic content and not by their quality or exergy. However, the exergy factors are all bigger than the unity except for thermal fluxes, meaning that the total exergetic content, in energy carriers, entering the nation should be slightly higher than the energetic one represented by the dots in Figure 2.

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Table 1. Methodologies used for the labour, capital, and environmental impact of published EEA studies. The aim of the study may be the process or sector efficiency1 or the EEC2 of a flux or process; the equivalent exergy of environmental impact is usually the trash and discharge (T&D)3 intrinsic exergy or the equivalent exergy of capital for garbage and waste (G&W)4 processing. eek (MJ/$)

Environmental Impact Method

52.7

18.2

3 times intrinsic exergy

Efficiency1

235.5

18.2

Discharge intrinsic exergy

-

-

-

Theoretical

235.5

18.2

T&D intrinsic exergy3

20.1

T&D intrinsic exergy3

18.2

T&D intrinsic exergy3

16.0 (€)

T&D intrinsic exergy3

Study, Region and Year

Input Exergy

Aims

Labour Methodology

Sciubba (2001) [6] Italy 1994

Intrinsic exergy

Efficiency1

Sciubba (2003a) [32] Italy 1998

Intrinsic exergy

Sciubba (2003b) [33]

-

eeL (MJ/h)

Capital Methodology

Sciubba (2004) [7] Italy 1998

Not explicit

Ertesvag (2005) [9] Norway 2000

Intrinsic exergy

Efficiency1

Milia and Sciubba (2006) [22] Italy 1996

Not explicit

Efficiency1

Sciubba et al. (2008) [23] Italy 2000

Intrinsic exergy

Efficiency1

Gasparatos et al. (2009) [10] UK 2004

Intrinsic exergy

Efficiency1

248.3

10.0 (£)

T&D intrinsic exergy3

Chen and Chen (2009) [24] China 2005

Intrinsic exergy

Efficiency1

71.9

23.7

G&W processing cost4

Dai and Chen (2011) [34]

Not explicit

EEC2

-

-

G&W processing cost4

Bligh and Ugursal (2012) [25] Canada 2006

Intrinsic exergy

Efficiency1

406.5

20.7 (C$)

T&D intrinsic exergy3

Ptasinski et al. (2006) [17] Netherlands, 1996

CExC, Intrinsic exergy

Efficiency1

EL=  ELW · Nw + ELSkillee+k ELSA

-

EK = C · eek eek = NREAin /IC

197–621 (€)

G&W processing cost4

Hoang and Alauddin (2011) [28]

CExC, Intrinsic exergy

Efficiency1

Equivalent Exergy of Labour ( J ): EL = Fe · Nw ttwt

-

-

-

Not applied.

Sciubba (2011) [30]

-

-

-

-

Not applied.

Sciubba (2012) [35]

-

-

-

Dai et al. (2012) [36]

Not explicit

EEC2

Efficiency1

Sciubba (2013) [37]

-

-

Dai et al. (2014) [20]

Manufacture cost

EEC2

Chen et al. (2014) [38] China 2000–2007

Intrinsic exergy

EEC2

Jawad et al. (2015) [39]

Intrinsic exergy

EEC2

EEC2 Equivalent Exergy of Labour ( J ): EL = Ein

525.8

Equivalent Exergy of Capital ( J ): Ek = C · eek

198.5 Specific exergy of labour ( J/h): ee L = EL /nworkhours

Equivalent Exergy of Labour ( J ): EL = αEin = f · esurv · Np Specific exergy of labour ( J/h): ee L = EL /nworkhours

253.0

52–76 -

Specific exergy of capital ( J/$): eek = Ein /M2

Equivalent Exergy of Capital ( J ): Ek = M2 · eek

-

Theoretical

-

Theoretical.

Specific exergy of capital ( J/$): α· β· E eek = M2 in = ESL

-

EEC of CO, NOX and SO2 .

42–23

G&W processing cost4

-

G&W processing cost4

G&W cost4 and T&D exergy3

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Table 1. Cont. eeL (MJ/h)

Capital Methodology

eek (MJ/$)

Environmental Impact Method

Efficiency1

153.9

25.5

G&W processing cost4

Intrinsic exergy

Efficiency1

153.9

25.5

EEC of CO2 , N2 O and CH4 .

Seckin and Bayulken (2013) [8] Turkey 2006

Intrinsic exergy

EEC2

153.9

Equivalent Exergy of Capital: Ek = ( M2 − S) · eek Specific exergy of capital ( J/$): α· β· E eek = M2−inS =

25.5

G&W cost4 and intrinsic exergy

Rocco et al. (2014) [18]

CExC

EEC2

-

-

Theoretical.

Study, Region and Year

Input Exergy

Aims

Seckin et al. (2012) [11] Turkey 2006

Intrinsic exergy

Seckin et al. (2013) [21] Turkey 2006

Labour Methodology

f ·esurv · Np S

=

EL S

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Energy (MJ per capita)

800000

400000

0 0.3

0.4

0.5

0.6 HDI

0.7

0.8

0.9

1

Figure Figure2.2.Comparison Comparisonbetween betweencountry’s country’senergy energyuse useby byenergy energycarriers, carriers,Ein* Ein*(in (inblue), blue),and andcountry’s country’s predicted energy use by HDI (2013), E (in red). L predicted energy use by HDI (2013), EL (in red).

For HDI values lower than 0.65, EL > Ein∗ , with a high probability of being higher than Ein (for For HDI values lower than 0.65, 𝐸 > 𝐸 , with a high probability of being higher than 𝐸 (for South Sudan, labour flux from HDI is 13 times ∗higher than all energy from energy carriers). For HDI South Sudan, labour flux from HDI is 13 times higher than all energy from energy carriers). For HDI values between 0.65 and 0.78, EL > Ein∗ for some countries while EL < Ein∗ for others. For HDI values values between 0.65 and 0.78, 𝐸 > 𝐸 for some countries while 𝐸 < 𝐸 ∗ for others. For HDI higher than 0.78, EL < Ein∗ , as expected. ∗Nevertheless, there is no observed linearity between HDI values higher than 0.78, 𝐸 < 𝐸 ∗ , as expected. Nevertheless, there is no observed linearity between and Ein∗ and for lower HDI countries EL > Ein∗ which is problematic. HDI and 𝐸 ∗ and for lower HDI countries 𝐸 > 𝐸 ∗ which is problematic. Rocco et al. [18], in their theoretical reassessment of EEA, also referred the lack of linearity between Rocco et al. [18], in their theoretical reassessment of EEA, also referred the lack of linearity HDI and the real energy consumption of a region and highlighted how the equivalent exergy of labour between HDI and the real energy consumption of a region and highlighted how the equivalent tends to rise with lower employment rates. exergy of labour tends to rise with lower employment rates. Human labour has a physical component which may be easily measured by its energy expenditure Human labour has a physical component which may be easily measured by its energy while working and an intellectual component comprising planning, managing, and all related expenditure while working and an intellectual component comprising planning, managing, and all intellectual activities which cannot be accounted in energy terms [41]. Number of workers and hours related intellectual activities which cannot be accounted in energy terms [41]. Number of workers worked are usually available in labour statistics. These quantities measured by number of persons and hours worked are usually available in labour statistics. These quantities measured by number of and hours need conversion factors if one wants to reflect on them as energetic or exergetic streams. persons and hours need conversion factors if one wants to reflect on them as energetic or exergetic Table 2 presents several options of accounting for exergy embedded on human labour (EL ). The first streams. Table 2 presents several options of accounting for exergy embedded on human labour (𝐸 ). line is the extra physical expenditure of energy while working while the second line includes also the The first line is the extra physical expenditure of energy while working while the second line basal metabolic rate. The third line considers the survival energy (or human energy requirements [42]) includes also the basal metabolic rate. The third line considers the survival energy (or human energy which is the average food energy required to satisfy energy expenditure, maintain body size (adult) requirements [42]) which is the average food energy required to satisfy energy expenditure, or physical growth (child) and be healthy while the fourth considers the metabolizable food energy maintain body size (adult) or physical growth (child) and be healthy while the fourth considers the intake during working hours (first column), total time (second column) and for total population (third metabolizable food energy intake during working hours (first column), total time (second column) column). These approaches are independent of the type of work. Approaches synthesized in the first and for total population (third column). These approaches are independent of the type of work. column cannot be considered as cumulative approaches because they only account for the power that Approaches synthesized in the first column cannot be considered as cumulative approaches because workers are “spending” during working hours. they only account for the power that workers are “spending” during working hours. Sciubba [30] chose a cumulative approach for labour energy, concluding that labour is only Sciubba [30] chose a cumulative approach for labour energy, concluding that labour is only possible by the presence of all population and used a conversion factor, from energy to exergy, based possible by the presence of all population and used a conversion factor, from energy to exergy, on the current HDI index over a preindustrial one. The HDI comprises lifestyle, education, and based on the current HDI index over a preindustrial one. The HDI comprises lifestyle, education, national income in one index. and national income in one index. According to the EEA methodology, the economy is divided in seven sectors (Extraction, AFF, According to the EEA methodology, the economy is divided in seven sectors (Extraction, AFF, Conversion, Industry, Transportation, Tertiary, and Domestic) plus two open systems responsible for Conversion, Industry, Transportation, Tertiary, and Domestic) plus two open systems responsible flux exchanges (Environment and Abroad). Human labour is the only output flow from the Domestic for flux exchanges (Environment and Abroad). Human labour is the only output flow from the sector which produces working hours that enables all sector’s economic activities. Domestic sector which produces working hours that enables all sector’s economic activities. The exergy needed to fuel society comes from the relation between the Environment and three The exergy needed to fuel society comes from the relation between the Environment and three economic sectors (Extraction, AFF, and Conversion) plus exergy trades with abroad. The exergy economic sectors (Extraction, AFF, and Conversion) plus exergy trades with abroad. The exergy surplus from these three sectors is consumed in the remaining four plus the abroad exergy trades. surplus from these three sectors is consumed in the remaining four plus the abroad exergy trades. The total primary exergy inflow to the society should be equal to the sum of all products’ CExC cost. The total primary exergy inflow to the society should be equal to the sum of all products’ CExC cost. Adding more exergy flows will double-count them. To deal with this issue, Rocco and Colombo [43] Adding more exergy flows will double-count them. To deal with this issue, Rocco and Colombo [43] have suggested a methodology to internalize labour in the economic system by assigning a fraction of have suggested a methodology to internalize labour in the economic system by assigning a fraction the domestic sector’s final demand to leisure activities and the rest to human labour which can provide of the domestic sector’s final demand to leisure activities and the rest to human labour which can provide a way around the double-counting issue if only the goods assigned to leisure activities are

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considered “final useful products”. In the first EEA methodology reviewed in this section, the a way around the double-counting issue if only the goods assigned to leisure activities are considered equivalent exergy of labour will introduce double-counting in the EEC because it increases the EEC “final useful products”. In the first EEA methodology reviewed in this section, the equivalent exergy of of products in two ways (directly and via labour). In the other methodologies, the existence or labour will introduce double-counting in the EEC because it increases the EEC of products in two ways absence of double-counting depends on whether the exergy used to fuel labour is also directly (directly and via labour). In the other methodologies, the existence or absence of double-counting attributed to useful products. depends on whether the exergy used to fuel labour is also directly attributed to useful products. Table 2. Embedded energy in human labour (𝑁 —Number of workers; 𝑁 —Total population; Table 2. Embedded energy in human labour (Nw —Number of workers; Np —Total population; 𝐸 —Exergy expenditure during labour; 𝐸 —Exergy expenditure at rest; 𝑡 —working time; Ew —Exergy expenditure during labour; Eb —Exergy expenditure at rest; tw —working time; tt —total —survival energy ≈ 2500kcal/d; 𝐹 —Food nutritional energy). 𝑡 —total time; 𝑒 time; esurv —survival energy ≈ 2500 kcal/d; Fe —Food nutritional energy).

Net energy cost of labour [44] Net energy cost of labour [44] Total energy expenditure [45] Total energy expenditure [45] Survivalenergy energy Survival Metabolized food energy Metabolized food energy

Working Time Working Time 𝑁 . (𝐸 𝐸 ). 𝑡 Nw · ( Ew − Eb ) · tw 𝑁 . 𝐸𝑛 . 𝑡 Nw · Enw · tw 𝑡 𝑁 Nw. ·𝑒esurv.. ttwt 𝑡 N Fe .·𝑡ttwt 𝑁w ·. 𝐹 𝑡

Total Time Total Time -

Total Population -

Total Population

𝑁w .· 𝑒esurv N N Fe 𝑁w ·. 𝐹

.𝑒 N𝑁 p · esurv Np𝑁· F. e𝐹

2.3. 2.3. Capital Capital Translating exergy fluxflux is also a challenging task. task. Seen as an input capital Translatingcapital capitaltotoanan exergy is also a challenging Seen as an factor, input the factor, the flux represents all capital services provided by tangible and intangible assets that depreciate their capital flux represents all capital services provided by tangible and intangible assets that depreciate ability to perform work over To quantify the equivalent exergy of capital, k , in the𝐸EEA their ability to perform worktheir overlifetime. their lifetime. To quantify the equivalent exergy of Ecapital, , in methodology, two issuestwo are issues addressed: (1) how to(1) quantify production factor capital in monetary the EEA methodology, are addressed: how tothe quantify the production factor capital in units, C, and (2) how to(2) quantify specific of exergy capital of needed convert units to monetary units, C, and how tothe quantify theexergy specific capitaltoneeded tomonetary convert monetary exergy units, ee . units to exergykunits, 𝑒𝑒 . We with thethe conversion of monetary to exergy units exploring a simpleaanalogy Wewill willstart start with conversion of monetary to exergy units exploring simple between analogy financial accounting and EEA (Figure 3). Three flows have a direct relation between a monetary flowa between financial accounting and EEA (Figure 3). Three flows have a direct relation between and energy as represented in Figure 3: intermediate consumption (IC), compensation of employees (S), monetary flow and energy as represented in Figure 3: intermediate consumption (IC), compensation and output. (S), and output. of employees Return to owners (€)

Investments (€)

Exergy flow Capital flow

Exergy of Natural Resources In (J) Intermediate Consumption (€) Equivalent Exergy of Labour (J) Compensation of Employees (€)

Exergy of Natural Resources Out (J)

System

Output (€)

Equivalent Exergy of Capital (J) Consumption of Fixed Capital (€)

Environmental Costs (J)

x Ta

(€) es

Subsidies (€)

Figure Figure 3. 3. Simplified analogy analogy between between financial financial accounting accounting and and Extended Extended Exergy ExergyAccounting. Accounting.

Intermediate (IC) consists of the value ofvalue services products Intermediateconsumption consumption (IC) consists ofmonetary the monetary of and services andconsumed products as inputs and used up byor a production process [46]. In the Natural Resources Exergy consumed as transformed inputs and or transformed used up by a production process [46]. In the Natural Accounting (NREA)Accounting methodology, this flow is quantified as an flow exergyisflow, representing matterflow, and Resources Exergy (NREA) methodology, this quantified as anall exergy energy plus services that enter the system [13]. If the ratio between these flows was used to obtain the representing all matter and energy plus services that enter the system [13]. If the ratio between these NREAin specific exergy eek = exergy , where NREA and energy flows in stands flows was usedoftocapital obtainthan the specific of capital than 𝑒𝑒 = for all, material where 𝑁𝑅𝐸𝐴 stands for IC measured by their intrinsic exergy. all material and energy flows measured by their intrinsic exergy. Compensation of employees (S) is the total remuneration payable in cash or in kind of wages, Compensation of employees (S) is the total remuneration payable in cash or in kind of wages, salaries, and social insurance contributions. In the EEA methodology, this flow, measured as exergy, is salaries, and social insurance contributions. In the EEA methodology, this flow, measured as exergy, the equivalent exergy of labour, EL . When the specific exergy of capital is obtained with these flows, is the equivalent exergy of labour, EL. When the specific exergy of capital is obtained with these eek = ESL , which is the relationship proposed by Scuibba (2011) and Seckin et al. (2013). flows, 𝑒𝑒 = , which is the relationship proposed by Scuibba (2011) and Seckin et al. (2013).

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Output is the monetary value of goods and services produced within a system for final use. out This flow is also quantified by its exergy in the NREA methodology. In this case, eek = NREA Output . From the previous analogy, three relations are possible: one based on the labour flow, eek = ESL ; in the other on the intermediate consumption of input goods and energy eek = NREA and finally the IC NREAout output relation eek = Output . The eek based on the IC or Output may be optimal for systems were the fluxes are all easily measured by their exergetic content. The eek based on output would have lower values since manufactured products have lower exergy than the sum of inputs but higher economical value. The eek based on labour uses the exergetic content of labour measured in a non “thermodynamic” way and provides values that depend on the economic context of the region under study. To relate a monetary value to an exergy quantity, Sciubba [6,32] used a specific exergy of capital eek = Ein /M2 ( J/$) and introduced the equivalent exergy of capital flow: Ek = C · eek ( J ) where C is the monetary flow under evaluation (Table 1). M2 is an intermediate monetary aggregate which reflects the currency under circulation plus the liquid deposits (maturity up to 2 years and redeemable up to 3 months) [47]. This approach to the equivalent exergy of capital is not related to financial accounting and is a macroeconomic value that may not be specified for each sector or subsector. Ertesvag [9] followed Sciubba [32] to quantify eek , the exergetic capital flow input, Ek,in , and the exergetic capital flow output, Ek,out . To quantify capital Ek,in , Ertesvag [9] used the sum of output, gross investment, and net subsidies as the “capital input” and the sum of intermediate consumption, compensation for employees, net taxes, return to owners, and consumption of fixed capital as “capital output”. To estimate the EEA efficiency, the author added “capital input” to other inputs and “capital output” to other outputs. Ertesvag was a pioneer since he applied, for the first time, the EEA approach for a nation, detailing all economic sectors and explaining all steps towards the exergetic assessment. It has become a reference study and most EEA researchers followed his methodology. However, by accounting for all monetary values entering and leaving the economic sectors, Ertesvag is double counting all material and energetic flows by their exergetic content and by their monetary value (Figure 3). This leads to incorrect values for the EEA efficiency (Table A20). The novelty of EEA is the inclusion of two fluxes, labour and capital, plus the exergy accounting of harmful environmental externalities. All three flows are regarded as inputs (production factors) except labour which also represents the output of the domestic sector (the NREA efficiency of the domestic sector only accounts recycling materials and is practically nil). In all other economic sectors, the NREA efficiency should be superior to the EEA efficiency since it doesn’t account for the equivalent exergy of harmful emissions as a virtual input nor the equivalent exergy of capital, representing the degradation of the capital stock or the capital services, or the equivalent exergy of labour. However, in the Ertesvag study [9], the opposite happened. Take as an example the Norwegian transportation sector, where the equivalent exergy of capital entering the sector is 64% of all input fluxes and an equivalent exergy of capital output was considered with almost the same amount. Adding such large numbers in both sides of the output-input equation ratio led to an overall increase of efficiency from 18.7% in NREA to 62.8% for EEA. The same behaviour was observed for all other economic sectors. Milia and Sciubba [22] analysed the exergetic efficiency of Italian society, for 1996, using the methodology proposed by Sciubba [6,32]. In this study, for the agricultural, industrial, and tertiary sectors, Ek,out > Ek,in , providing no explanation of the monetary flows that were used to quantify Cout and Cin . Sciubba et al. [23] applied the same methodology [6] to the Siena province. Here, the industry and transportation sectors also had more exergetic capital output than input, which, as in the previous study, may be related with the accounting method for Cout and Cin . Bligh and Ugursal [25], studying the economy of Nova Scotia, accounted Cout for the domestic sector as the sum of net subsidies, depreciation, and value of production while Cin , from the other sectors is the sum of intermediate consumption, capital expenditures, and return on investment to owners. This methodology led to Ek,out > Ek,in for all sectors except the domestic and conversion. The relative size of capital exergetic fluxes when compared with the other flows led to higher Efficiency for EEA. Appendix C presents the

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capital input-output relations and the efficiencies’ relations between NREA and EEA of all economic sectors and societal studies. Ptasinski et al. [17] assumed that: eek = NREAin /IC and that the C in Ek = C · eek was measured by the capital stock plus the short-term investment monetary values times the specific exergy of capital. Capital stock is the company’s capital (common and preferred stock a company is authorized to issue) and short-term investments is the money spent on tangible assets on that year. In his revision of the EEA methodology, Sciubba [30] assumed a proportionality between the equivalent exergies of capital and labour, Ek = β · EL , where β is given by β = M2/S. In this new method, the equivalent exergy of capital is smaller than the incoming global exergy Ek = α · β · Ein Ek Ein = α · β · M2 = ESL . The novelty is the relation and that the new specific capital exergy is: eek = M2 between the specific exergy of capital and the specific exergy of labour: eek = ee L nworkhours . With this S relationship, the specific exergy of capital can be easily estimated from the specific exergy of labour for individual sectors. Seckin et al. [21], in their assessment of the Turkish transportation sector, introduced a slightbut k meaningful change to the specific exergy of capital eek = M2E− S . Total salaries (S) were removed from the total current societal money (M2) because labour exergy was already accounted for. This change removed the issue of double-counting labour inputs. In Seckin et al. [21], the relationship, eek = ESL = ee L nworkhours was verified. S In the first EEA methodology reviewed in this section, the equivalent exergy of capital will introduce double-counting in the EEC because it increases the EEC of products in two ways (directly and via capital). In the other methodologies, double-counting is also an issue because all materials and energy for each sector are double counted by their intrinsic exergy and by their monetary (translated into exergy) cost. To avoid double-counting, a methodology is need to internalize capital, so that capital (a production factor) is also a product of the system. 2.4. Environmental Impact Environmental impact is defined by the EEA, as the exergy needed for the treatment process, taking into account all materials, energy, labour, and capital necessary, to avoid the pollutants emission or bring all pollutants to a dead state. EEA does not value harmful emissions by their physical and chemical exergies because these do not value the pollutants’ toxicity nor the devastating effects on our environment. However, real processes to completely avoid or treat effluents are non-existing or scarce. Although the specific exergy cost of pollutants is solely based on the exergetic resource consumption and independent of pollutants’ proprieties, the approach is a valuable step towards the societal cost of avoiding its environmental effects. For example, the value obtained for the EEC of biomass-based electricity would be lower than the EEC of coal-based electricity because the latter would take into account the exergy needed to remove the CO2 emissions associated with the combustion of coal. This lack of real processes presents a difficulty to EEA studies in their environmental assessment and allows multiple interpretations (Table 1). Two trends were followed to evaluate the trash and discharge fluxes to the environment. The first quantified their intrinsic exergies due to the lack of extended exergy cost values. The second converted the monetary costs associated with waste and pollutants management into exergy using the capital conversion factor. Three studies obtained the extended exergy cost of major atmospheric pollutants and wastewater. The environmental remediation cost values of carbon monoxide, mono-nitrogen oxides, and sulphur dioxide were published by Dai et al. (2014) [20] while carbon dioxide, nitrous oxide and methane were studied by Seckin et al. (2013) [21]. The extended exergy cost values of municipal wastewater and sludge abatement were obtained for Turkey in 2006 [8]. 3. EEA Methodologies: A Case Study We compare the EEA methodologies that were collected in Table 1 to estimate the efficiency of the Portuguese Agriculture, Forestry, and Fisheries (AFF) sector from 2000 to 2012. The exergy

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We compare the EEA methodologies that were collected in Table 1 to estimate the efficiency of the Portuguese Agriculture, Forestry, and Fisheries (AFF) sector from 2000 to 2012. The exergy flow flow diagram followed presented in Figure 4 [13],where whereall allavailable availablefluxes fluxes in in the diagram followed the the oneone presented in Figure 4 [13], the respective respective databases were accounted for and converted to energetic and exergetic fluxes. Data sources and values databases were accounted for and converted to energetic and exergetic fluxes. Data sources and gathered for this study are available in Appendixs A and B. values gathered for this study are available in Appendixes A and B.

Figure 4. EEA flow diagram applied to the Portuguese AFF sector [13]. Figure 4. EEA flow diagram applied to the Portuguese AFF sector [13].

Previous agricultural studies accounted for all agricultural produced fluxes as an output from the environment and as an input accounted to the agricultural sector. Inproduced this study, we as consider thatfrom all Previous agricultural studies for all agricultural fluxes an output renewable fluxes produced agricultural boundaries arethis an output from the sector the environment and as anwithin input the to the agricultural sector. In study, we consider thatand all are not extracted from the environment. The reason is that, ifare noan agricultural activities occurred, renewable fluxes produced within the agricultural boundaries output from the sector and are the produced fluxes would almostisnegligible. same thinking was applied the to not agricultural extracted from the environment. Thebereason that, if no The agricultural activities occurred, forestry (andproduced aquaculture) butwould not to be fisheries, there are human related activities the agricultural fluxes almost since negligible. Theno same thinking was applied within to forestry fisheries subsector but to feed eventually protect Fishing is anactivities extraction fromthe thefisheries natural (and aquaculture) not and to fisheries, since therethe arefishes. no human related within environment metals minerals. This methodology an efficiency which much subsector tolike feed and or eventually protect the fishes.inevitably Fishing leads is an toextraction from the isnatural lower than thelike efficiency for forestry or agricultureinevitably since fish catch as an output andis environment metalsobtained or minerals. This methodology leads appears to an efficiency which also as lower an input. much than the efficiency obtained for forestry or agriculture since fish catch appears as an output also as an input. for labour, capital, and environmental costs are the ones synthesized in Theand estimation methods estimation methods labour, capital, and environmental costs areexergies. the onesThe synthesized in Table The 1. Table 3 summarizes thefor equations used to estimate the AFF equivalent equivalent Table exergy 1. Table summarizes equations to of estimate AFFsector equivalent exergies. The labour of 3each subsector isthe defined as theused fraction workersthe in that times the equivalent equivalent labour exergyInofEEA1, each no subsector is defined fluxes as thewere fraction of workers sector times labour exergy of society. output monetary considered andin thethat only monetary the equivalent labour society. EEA1, no output fluxesofwere and input, representing theexergy assets of used in theInAFF sector, was themonetary consumption fixedconsidered capital (CFC). theEEA2, only monetary input, representing the assets used in the AFF sector, was the consumption of In the AFF money aggregate M2 is estimated as being proportional to M2 where the AFF fixed capital (CFC). In EEA2, theratio AFF of money M2 AFF is estimated as being proportional to proportionality coefficient is the AFF aggregate gross value added to aggregated gross added value. M2 equations where the presented proportionality coefficient is the the AFF ratio economic of AFF gross value aggregated All in Table 3 are for sector butadded were to also used for gross each added value. All equations presented in Table are for the AFF economic sector but were also used individual subsector (Agriculture, Forestry, and3Fishing). for each individual subsector (Agriculture, Fishing). As environmental remediation costs forForestry, the threeand EEA methodologies, this study considers the environmental remediation forAFF the sector three EEA methodologies, this study considers majorAs atmospheric pollutants emittedcosts by the and the respective specific exergy to cleanthe or major atmospheric emitted by the AFF sector and respectiveexergy specific exergy to include clean or prevent them. Thesepollutants specific exergy values were measured as the an extended cost so they prevent them. These exergy values were[20,21]. measured as an extended exergy cost so they the regional labour andspecific capital considered in Refs. include the regional labour and capital considered in Refs. [20,21].

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Table 3. EEA Methodologies applied to the AFF Portuguese sector (IEEA—Intrinsic Extended Exergy Accounting; M&E—Mass and Energy; EI—Environmental impact and EEC—Extended exergy cost). EEA Method

AFF Labour Exergy

EEA 1

AFF,workers EL,AFF = Ein · ntotal,workers ee L = EL,AFF /nworkhours,AFF

n

EEA 2

n

AFF,workers EL,AFF = f · esurv · Np . ntotal,workers ee L = EL,AFF /nworkhours,AFF

EEA 3

IEEA

EL,AFF = esurv · n AFF,workers ·

tw tt

AFF Capital Exergy

AFF Mass, Energy and Environmental Impact Exergies

Ek,AFF = CFC AFF · eek Ein eek = M2

M&E-Intrinsic Exergy EI-EEC

Ek,AFF = M2 AFF · eek eek = EL,AFF /S AFF AFF M2 AFF = M2 GVA GVA

M&E-Intrinsic Exergy EI-EEC

Ek,AFF = ( M2 AFF − S AFF ) · eek ek = EL,AFF /S AFF AFF M2 AFF = M2 · GVA GVA

M&E-Intrinsic Exergy EI-EEC

Ek,AFF = CFC AFF · eek = in CFC AFF · NREA IC

Intrinsic Exergy

In these EEA approaches, energy and material fluxes are valued by their intrinsic exergy while the three immaterial ones are valued using arbitrary assumptions that were not fully justified. We define a new methodology (IEEA) to measure the capital, labour, and environmental impact flows. This methodology evaluates all fluxes by an intrinsic approach in order to allow more consistent efficiency measurements of single processes. The equivalent exergy of labour is considered to be an output of the domestic sector and fed by some of the incoming exergy to the sector. It is measured by the worker’s survival exergy while working. The energy needed to sustain the workers is just for working days (235 days yearly considered) and during work hours (8 h daily). To maintain consistency with the remaining input fluxes, the equivalent exergy of capital is considered to be the “consumed” intrinsic exergy of capital assets. However, since it is impossible to measure this flux by physical proprieties, we will use the consumption of fixed capital multiplied by the specific exergy of capital (Table 3), eek = NREAin /IC. The consumption of fixed capital (CFC) represents the lifetime share of the tangible and intangible assets used as a production factor, while the choice of eek is based on the assumption that the specific intrinsic exergies of intermediate consumption and fixed capital are similar. Mass and energy flows can be easily converted from energy to exergy (Appendix A). Environmental impact follows the same approach (Table 3). In the IEEA, the environmental impact methodology is extended to include carbon dioxide sequestration from the forestry subsector. This will reflect the importance of the AFF sector not only in its ability to nourish all humankind but also through its remarkable ability to convert carbon dioxide into carbohydrates. Carbohydrates will produce cellulose (based on carbon), a primary component of plant cells. Although the carbon dioxide concentration in the atmosphere just recently surpassed 0.04% [48], it is increasing and may be related to global warming and climate changes. Once carbon dioxide is considered a harmful pollutant when released, it should also be considered an environmental service when sequestered. Thus, the AFF sector produces an environmental virtual output service, an environmental benefit (EB) that has to be taken into account. The environmental benefit (EB) is estimated by multiplying the CO2 sequestered by the EEC (in EEA methodologies) or the specific exergy (in IEEA). Since crops, vegetable, and fruits are intended for human consumption and our metabolism frees the ingested carbon, we will not account it as an exergetic sequestered flux. However, wood follows a commercial or industrial path mainly as a resource or energy carrier. If wood is used for furniture or construction it maintains its carbon content; if used in combustion processes as an energy carrier or in the paper industry, the released carbon dioxide should be attributed to the related activity.

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4.Results, Comparison, and Discussion Discussion 4.4.Results, Results, Comparison, Comparison, and and Discussion 4.1. The Exergy of Material Fluxes 4.1. The TheExergy ExergyofofMaterial MaterialFluxes Fluxes 4.1. Figure 5 presents the amount of intrinsic exergy in materials and energy entering the AFF sector Figure 5 presents ofof intrinsic exergy in materials and and energy entering the AFF sector presents the theamount amount intrinsic in and materials energy entering AFF [13].Figure These exergetic fluxes take into account exergy the mass energy magnitudes and thethespecific [13]. These exergetic fluxes taketake intointo account thethe mass and energy magnitudes and specific sector [13]. These exergetic fluxes account mass and energy magnitudes and the specific exergy values as explained in Appendix A. Feed is the main contributor with more than half of all exergy values values as asexplained explained in in Appendix Appendix A. A. Feed Feed isis the the maincontributor contributor with with more more than than half of ofall all exergy exergy into the sector, followed by energy carriers.main The intrinsic energy of seeds, half fertilizers, exergy into the sector, followed by energy carriers. The intrinsic energy of seeds, fertilizers, exergy into the by energy carriers. The intrinsic energy of seeds, fertilizers, pesticides, pesticides, andsector, fish isfollowed almost negligible. pesticides, and fish is almost negligible. and fish is almost negligible.

Exergy (TJ) Exergy (TJ)

80000 80000

seeds seeds

67500 67500

fertilizers fertilizers

pesticides pesticides

fish fish

energy energy

55000 55000 42500 42500

feed feed 30000 30000 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2000 2001 2002 2003 2004 2005 Year 2006 2007 2008 2009 2010 2011 2012

Year

Figure 5. Exergy of all materials and energy entering the AFF sector [13]. Figure Figure5.5. Exergy Exergyof ofall allmaterials materialsand andenergy energyentering enteringthe theAFF AFFsector sector[13]. [13].

4.2.The TheExergy ExergyofofImmaterial ImmaterialFluxes Fluxeswith withEEA1, EEA1,EEA2, EEA2,and andEEA3 EEA3 4.2. 4.2. The Exergy of Immaterial Fluxes with EEA1, EEA2, and EEA3 The exergy exergyofofenvironmental environmentalimpact, impact, common common totoEEA EEAmethodologies, methodologies, presents presents the the two two The The exergy of environmental impact, common to EEA methodologies, presents the two atmosphericpollutants pollutants that have highest overall EEC: carbon dioxide and methane (Figure atmospheric that have thethe highest overall EEC: carbon dioxide and methane (Figure 6) [13].6) atmospheric pollutants that have the highest overall EEC: carbon dioxide and methane (Figure 6) [13]. Thepollutants: other pollutants: carbon hydrofluorocarbons monoxide, hydrofluorocarbons (COnitrous 2 equivalent), The other ammonia,ammonia, carbon monoxide, (CO2 equivalent), oxide, [13]. The other pollutants: ammonia, carbon monoxide, hydrofluorocarbons (CO2 equivalent), nitrous oxide, oxides, and are sulphur areAlso, barely Also,subsector the agriculture subsector nitrogen oxides,nitrogen and sulphur oxides barelyoxides visible. thevisible. agriculture represents 77% nitrous oxide, nitrogen oxides, and sulphur oxides are barely visible. Also, the agriculture subsector 77% to 87% of the total virtual exergy. Methane emissions follow trend line of animal torepresents 87% of the total virtual exergy. Methane emissions follow the trend linethe of animal husbandry represents 77% to 87% of the total virtual exergy. Methane emissions follow the trend line of animal husbandry (almost production (almost constant) carbon dioxide the decreasing consumption production constant) and carbon and dioxide follows thefollows decreasing consumption trend of husbandry production (almost constant) and carbon dioxide follows the decreasing consumption trend resources of energyon resources all threeOver subsectors. Overperiod, the 13-year period, forestry reduced its energy all three on subsectors. the 13-year forestry reduced its virtual exergy trend of energy resources on all three subsectors. Over the 13-year period, forestry reduced its virtual exergy consumption by 60%, fisheries by 40%, and agriculture by 10% which resulted in an consumption by 60%, fisheries by 40%, and agriculture by 10% which resulted in an overall reduction virtual exergy consumption by 60%, fisheries by 40%, and agriculture by 10% which resulted in an reduction ofoverall 18% (Figure 6). of 18% (Figure 6). overall reduction of 18% (Figure 6).

Environmental Environmental Impact Exergy (TJ) Impact Exergy (TJ)

180000 180000 120000 120000 60000 60000

Agriculture Agriculture

Methane Methane Carbon dioxide Carbon dioxide

Fishery Fishery Forestry 0 0 2000 Forestry 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2000 2001 2002 2003 2004 2005 Year 2006 2007 2008 2009 2010 2011 2012

Year

Figure Figure6.6.The Thevirtual virtualexergy exergyinput inputdue duetotopollutant pollutantemissions emissionsinto intoAFF AFFsubsectors subsectors[13]. [13]. Figure 6. The virtual exergy input due to pollutant emissions into AFF subsectors [13].

The exergy of of labour hashas twotwo different methodologies (Table 3). In 3). EEA1, EL is the Theequivalent equivalent exergy labour different methodologies (Table In EEA1, EL total is the Theofequivalent exergythe ofsociety labour (E has two different methodologies (Table 3). In EEA1, E L is the amount exergy entering ) while in EEA2,3 it is only a fraction of E which explains in in total amount of exergy entering the society (𝐸 ) while in EEA2,3 it is only a fraction of 𝐸 which total amount of exergy entering thefor society (𝐸 ) while in EEA2,3 it decrease is only a in fraction of 𝐸 which the higher values obtained EEA1 allEEA1 subsectors 7). The exergy from explains the higher valuesfor obtained for for all(Figure subsectors (Figure 7). Thelabour decrease in labour explains the higher values obtained for EEA1 for all subsectors (Figure 7). The decrease in labour EEA1 since 2005 is mainly due to a decrease in E (Appendix B). The difference between subsectors is in exergy from EEA1 since 2005 is mainly due to a decrease in 𝐸 (Appendix B). The difference from of EEA1 since 2005 is mainly due to a decrease in 𝐸 (Appendix B). The difference aexergy direct result the number of workers. between subsectors is a direct result of the number of workers. between subsectors is a direct result of the number of workers.

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Equivalent exergy of Labour Equivalent exergy Labour Equivalent exergy ofof Labour by methodology methodology (TJ) (TJ) byby methodology (TJ)

EEA1 Agriculture 7000 160000 6000 110000 7000 160000 EEA1 Agriculture EEA2,3 Agriculture EEA1 Agriculture 6000 110000 5000 60000 6000 110000 EEA2,3 Agriculture EEA1 Fishing EEA2,3 Agriculture 5000 60000 4000 10000 5000 60000 EEA1 Fishing 4000 10000 EEA1 Fishing 3000 -40000 EEA1 Forestry 4000 10000 3000 -40000 2000 -90000 EEA1 Forestry EEA2,3 Fishing 3000 -40000 EEA1 Forestry EEA2,3 Forestry 2000 -90000 EEA2,3 Fishing 1000 -140000 2000 -90000 EEA2,3 Fishing 2000 2001 2002 2003 2004 2005 2006 EEA2,3 2007 Forestry 2008 2009 2010 2011 2012 1000 -140000 EEA2,3 Forestry 10002000 2001 2002 2003 2004 2005 Year -140000 2006 2007 2008 2009 2010 2011 2012 2000 2001 2002 2003 2004 2005 Year 2006 2007 2008 2009 2010 2011 2012 Figure 7. Equivalent exergy of labour per EEA methodology and subsector (full lines on the left axis Year and dashed lines on the rightofaxis). Figure 7. Equivalent exergy labour per per EEA methodology methodology and subsector subsector (full lines lines on the the left axis axis Figure Figure7.7.Equivalent Equivalentexergy exergyof oflabour labour perEEA EEA methodologyand and subsector(full (full lineson on theleft left axis and dashed lines on the right axis). and on axis). anddashed dashedlines lines onthe the right axis). The specific exergy ofright labour, 𝑒𝑒 , which is the exergy needed to sustain one hour of labour is

increasing for EEA1 and EEA2,3 (Figure 8). Theisnumber of workers per subsector almost constant The specific specific exergy of labour, labour, 𝑒𝑒L , ,which which theexergy exergy needed to to sustain sustain oneishour hour of labour labour is The exergy of ee is the needed one of is The specific exergy of labour, 𝑒𝑒 , which is the exergy needed to sustain one hour of labour (except for for agriculture which is slightly decreasing) but of theworkers annual per working hours per worker areis increasing EEA1 and EEA2,3 (Figure 8). The number subsector is almost constant increasing for EEA1 and EEA2,3 (Figure 8). The number of workers per subsector is almost constant increasing for EEA1 and EEA2,3 (Figure 8). The decrease number of per subsector is almost constant decreasing. From 2000 to 2012isthere was decreasing) a 30% inworkers agriculture, 3% inhours forestry, 13%are in (except for for agriculture agriculture which slightly but the the annual working working per and worker (except which is slightly decreasing) but annual hours per worker are (except for agriculture which is slightly decreasing) but the annual working hours per worker are fisheries. Since the average work hours per worker is lower agriculture, is higher in decreasing. From there was 30% decrease in in agriculture, 3%itsin in𝑒𝑒 forestry, and(30% 13% in in decreasing. From 2000 2000 to to 2012 2012 there was aa 30% decrease in agriculture, 3% forestry, and 13% decreasing. From 2000subsectors. to 2012 there was a 30% decrease in agriculture, 3% in forestry, and 13% in 2012) than in the other fisheries. Since Since the is higher higher (30% (30% in in fisheries. the average average work work hours hours per per worker worker is is lower lower in in agriculture, agriculture, its its 𝑒𝑒 ee is fisheries. Since the average work hours per worker is lower in agriculture, its 𝑒𝑒L is higher (30% in 2012) than in the other subsectors. 2012) than in the other subsectors. 2012) than in the other subsectors. EEA1 Agriculture 175

Specific exergy Specific exergy Specific exergy ofof of Labour (TJ/1000hrs) Labour (TJ/1000hrs) Labour (TJ/1000hrs)

EEA1 AFF EEA1 Agriculture 175 150 EEA1EEA1 Agriculture EEA1 AFF Fisheries 175 EEA1 AFF 150 125 EEA1 Forestry EEA1 Fisheries 150 EEA1 Fisheries 125 100 EEA1 Forestry EEA2,3 125 EEA1 Forestry Agriculture EEA2,3 AFF 100 75 Agriculture EEA2,3 Fisheries 100 EEA2,3 EEA2,3 Agriculture EEA2,3 AFF Forestry 75 50 EEA2,3 Fisheries EEA2,3 AFF 75 Fisheries 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009EEA2,3 2010 2011 2012 EEA2,3 Forestry 50 Year EEA2,3 Forestry 502000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 YearEEA Figure 8. Specific exergy of labour per methodology and subsector. Year Figure Figure 8. 8. Specific Specific exergy exergy of of labour labour per per EEA EEA methodology methodology and and subsector. subsector.

Figure 8. Specific exergy of labour per EEA methodology and subsector. The differences between the equivalent exergies of capital, between the EEA methodologies, are differences between the equivalent exergies of capital, between the methodologies, are very The significant (Figure 9). The equivalent exergy of capital in agriculture in EEA2 is 26% to 47% The differences between the equivalent exergies of capital, between the EEA EEA methodologies, are The differences between the equivalent exergies of capital, between the EEA methodologies, are very significant (Figure 9). The equivalent exergy of capital in agriculture in EEA2 is 26% to 47% higher higher than in EEA3 to 18% higherexergy in forestry and in 51% to 68% higher in isfishery). The very significant (Figure(14% 9). The equivalent of capital agriculture in EEA2 26% to 47% very significant (Figure 9). The equivalent exergy of capital in agriculture in EEA2 is 26% to 47% than in EEA3 (14% to 18% higher in forestry and to lower 68% higher The equivalent exergy equivalent of capital in is several times than the other methodologies. Not higher thanexergy in EEA3 (14% to EEA1 18% higher in 51% forestry and 51% intofishery). 68% higher in fishery). The higher than in EEA3 (14% to lower 18%lower higher in forestry and 51% to 68% higher inspecific fishery). The of capital in EEA1 is several times than in the other methodologies. Not only is the exergy only is the specific exergy of capital in EEA1 (Figure 10), but the monetary flux is also lower equivalent exergy of capital in EEA1 is several times lower than in the other methodologies. Not equivalent exergy of capital in EEA1 is several times lower than in the other methodologies. Not of capital lower in EEA1 (Figure 10), but the monetary flux is also lower for all subsectors (CFC < M2). for allissubsectors (CFC < M2). only the specific exergy of capital lower in EEA1 (Figure 10), but the monetary flux is also lower only is the specific exergy of capital lower in EEA1 (Figure 10), but the monetary flux is also lower for all subsectors (CFC < M2). for all subsectors (CFC < M2). 17500 320000

Equivalent Exergy Equivalent Exergy Equivalent Exergy ofof of Capital by methodology Capital methodology Capital byby methodology (TJ) (TJ) (TJ)

EEA2 Agriculture 15000 230000 17500 320000 EEA3 Agriculture 17500 320000 EEA2 Agriculture 12500 140000 15000 230000 EEA2 Agriculture EEA3 Agriculture EEA2 Forestry 15000 230000 10000 50000 Agriculture 12500 140000 EEA3 EEA3 Forestry 12500 140000 EEA2 Forestry 7500 -40000 10000 50000 EEA2 Forestry EEA1 Agriculture EEA3 Forestry 10000 50000 EEA2 Fishing 5000 -130000 EEA3 Forestry 7500 -40000 EEA1 Agriculture 7500 -40000 EEA3 Fishing EEA2 Fishing 2500 -220000 5000 -130000 EEA1 Agriculture EEA1 Forestry EEA2 Fishing 5000 -130000 EEA1 Fishing EEA3 Fishing 0 -310000 2500 -220000 EEA3 Fishing EEA1 Forestry 25002000 2001EEA1 -220000 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Fishing EEA1 Forestry 0 -310000 Year EEA1 Fishing 02000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 -310000 Year 2000 2001exergy 2002of 2005methodology 2006 2007 and 2008 2009 2010 2011on 2012 Figure exergy capital per subsector (full lines lines the left axis Figure 9. 9. Equivalent Equivalent of2003 capital2004 per EEA EEA methodology and subsector (full on the left axis Year and dashed lines on the right axis). and dashed lines on the rightofaxis). Figure 9. Equivalent exergy capital per EEA methodology and subsector (full lines on the left axis Figure 9. Equivalent exergy of capital per EEA methodology and subsector (full lines on the left axis and dashed lines on the right axis). and dashed lines on the right axis).

Specific exergy of of of Specific exergy Specific exergy capital - eek (TJ/M€) capital - eek (TJ/M€) capital - eek (TJ/M€)

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EEA2,3 Agriculture EEA2,3 Agriculture EEA2,3 Agriculture

EEA2,3 AFF EEA2,3 AFF EEA2,3 AFF

EEA2,3 Forestry EEA1 EEA2,3 Fishing EEA2,3 Forestry EEA2,3 Forestry EEA1 2001 EEA2,3 2002 Fishing 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 EEA1 Year EEA2,3 Fishing 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2001 2002 2003 2004 2005 Year 2006 2007 2008 2009 2010 2011 2012 Figure 10. Specific exergy of capitalYear per EEA methodology and subsector. Figure 10. Specific exergy of capital per EEA methodology and subsector. Figure 10. 10. Specific Specific exergy exergy of capital capital per per EEA EEA methodology methodology and and subsector. subsector. Figure The differences among the specificofexergies of capital values are high (Figure 10). While in

Annual average salary Annual average salary Annual average salary perper worker (1000€) per worker (1000€) worker (1000€)

The differences among the specific exergies of=capital values are high (Figure 10). While in EEA1The there is only one ee the for all subsectors, 𝑒𝑒 capital 𝐸 values /𝑀2, in and EEA3 is possible to differences among specific exergies of areEEA2 high (Figure 10).itWhile in EEA1 The differences among the specific exergies of capital values are high (Figure 10). While in EEA1isthere only one ee subsectors, for all subsectors, 𝐸 /𝑀2, in EEA2 and is to possible to subsector. in=the subsector earnsit about 8 times estimate 𝑒𝑒 is , = eek for there only one for each all eeAk1worker = Ein𝑒𝑒/M2, in agriculture EEA2 and EEA3 it isEEA3 possible estimate EEA1 there one ee for all subsectors, 𝑒𝑒 in=the 𝐸 /𝑀2, in EEA2 and EEA3 it about is possible to EL𝑒𝑒 is, only = for each subsector. A worker agriculture subsector earns 8 times estimate less fisheries and 6 times less than in forestry (Figure 11). These are reflected ee = Sinfor each subsector. A worker in the agriculture subsector earnsdifferences about 8 times less than on in k2,3than for each subsector. A worker in the agriculture subsector earns about 8 times estimate 𝑒𝑒 , = less than in fisheries and 6 times less than in forestry (Figure 11). These differences are reflected on the specific exergies of capital. The average annual salary for agriculture is low because many fisheries and 6 times less than in forestry (Figure 11). These differences are reflected on the specific less in capital. fisheries and 6salaries. times less than in forestry (Figure 11). differences reflected on the than specific exergies of average capital. The average annual salaryannual foris These agriculture ismany loware because many farmers have no declared Both fishing and forestry salaries are more realistic in the exergies of The annual salary for agriculture low because farmers have the specific exergies of capital. The average annual salary for agriculture is low because many farmers have no declared salaries. Bothforestry fishing annual and forestry annual salaries are more realistic in the Portuguese economic context. no declared salaries. Both fishing and salaries are more realistic in the Portuguese farmers have no declared salaries. Both fishing and forestry annual salaries are more realistic in the Portuguese economic context. economic context. Portuguese economic context. 13 13 10 13 10 107 7 74 4 41 12000 1 2000 2000

Forestry Forestry Forestry

Fishing Fishing Fishing

Agriculture Agriculture 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Agriculture 2001 2002 2003 2004 2005 Year 2006 2007 2008 2009 2010 2011 2012 2001 2002 2003 2004 2005 Year 2006 2007 2008 2009 2010 2011 2012 Figure 11. Annual average salary Yearper worker and subsector. Figure Figure 11. 11. Annual Annual average average salary salary per per worker worker and and subsector. subsector. Figure 11. Annual average salary per worker and The equivalent capital exergy of forestry is substantially higher subsector. than fisheries (Figure 9) because

Gross Value Added Gross Value Added Gross Value Added perper annual salaries per annual salaries annual salaries

The equivalent capital exergy of forestry is substantially higher than fisheries (Figure 9) because equivalent capitalexergy exergyofoflabour forestry is substantially thanand fisheries (Figure 9) because it hasThe a higher equivalent (higher number ofhigher workers) a higher fraction of M2 it hasThe a higher equivalent exergy ofoflabour (higher number ofhigher workers) and a higher fraction of M2 equivalent capital exergy forestry is substantially than fisheries (Figure 9) because it has a GVA). higher Figure equivalent exergy the of labour number of workers) a higher ofand M2 (higher 12 presents ratio of(higher gross value added to annualand salaries per fraction subsector (higher Figure 12 presents the ratio of(higher gross value added to annual salaries per fraction subsector and it has a GVA). higher equivalent exergy of number offorestry, workers) and a higher M2 (higher GVA). Figure 12 presents thelabour ratio of gross value added to annual salaries per subsector and explains the higher equivalent exergy of capital in forestry. In for every monetary unitof spent explainsGVA). the higher equivalent exergy of capital in forestry. In forestry, for every monetary unit spent (higher 12become presents the ratio of gross value added to annual salaries per subsector and explains the6higher equivalent exergy of capital indecreasing forestry. Inslopes forestry, monetary spent on salaries, toFigure 9 units value-added. The arefor dueevery to a decrease inunit GVA for on salaries, 6 to 9 units become value-added. The decreasing slopes are due to a decrease in GVA for explains the 6higher equivalent of capital in decreasing forestry. In slopes forestry, every unit spent on subsectors. salaries, to 9 units becomeexergy value-added. The arefor due to a monetary decrease in GVA for all all subsectors. on 6 to 9 units become value-added. The decreasing slopes are due to a decrease in GVA for all salaries, subsectors. all subsectors. 8 8 86 6 64 4 42 22000 2 2000 2000

Forestry Forestry Forestry Agriculture Fishery Agriculture Fishery Agriculture Fishery2002 2003 2004 2005 2006 2007 2008 2009 2010 2001 Year 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Year 2001 2003 2004value 2005 2007salaries 2008per 2010 Figure 12. Ratio of gross added by subsector. Figure2002 12. Ratio of gross value added2006 by annual annual salaries per2009 subsector.

Year

2011 2011 2011

2012 2012 2012

Figure 12. Ratio of gross value added by annual salaries per subsector. 4.3. The Additional Figure Immaterial Flux:ofThe Environmental Benefit (EB) 12. Ratio gross value added by annual salaries per subsector. 4.3. The Additional Immaterial Flux: The Environmental Benefit (EB)

TheAdditional environmental benefit (EB) sequesteringBenefit carbon(EB) dioxide by wood removal is 2.2 to 3.3 4.3. The Immaterial Flux: TheofEnvironmental TheAdditional environmental benefit sequesteringBenefit carbon dioxide by wood removal is 2.2 to 3.3 4.3. The Immaterial Flux:(EB) The of Environmental times larger than the entire environmental impact of the AFF(EB) sector (Figure 13). The EB value is larger environmental benefit (EB) of sequestering dioxide wood 13). removal is 2.2 to 3.3 timesThe larger than the entire environmental impact ofcarbon the AFF sectorby (Figure The EB value is than The all inputs of the sector and reflects itssequestering importance which was, until by now, neglected in these studies. environmental benefit (EB) of carbon dioxide wood removal is 2.2 to 3.3 times larger than the of entire environmental impact of the AFF which sector was, (Figure 13). Theneglected EB value in is larger than all inputs the sector and reflects its importance until now, times than the entire impact of the AFF which sector (Figure 13).now, The neglected EB value is largerlarger than all inputs of the environmental sector and reflects its importance was, until in larger than all inputs of the sector and reflects its importance which was, until now, neglected in

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Environmental benefit benefit Environmental (TJ) of sequestering sequestering CO CO22(TJ) of

these these studies. studies. In In Portugal, Portugal, due due to to the the strong strong paper paper industry, industry, the the difference difference between between removals removals of of non-coniferous and wood almost tripled from to the In Portugal, due wood to the strong paper industry, difference between removals of non-coniferous wood non-coniferous wood and coniferous coniferous woodthe almost tripled from 2000 2000 to 2012, 2012, the total total remaining remaining almost constant. and coniferous wood almost tripled from 2000 to 2012, the total remaining almost constant. almost constant. 400000 400000 non-coniferous non-coniferous 300000 300000 200000 200000 coniferous coniferous 100000 100000 2000 2000 2001 2001 2002 2002 2003 2003 2004 2004 2005 2005 2006 2006 2007 2007 2008 2008 2009 2009 2010 2010 2011 2011 2012 2012

Year Year

Environmental Figure Figure13. 13.Environmental Environmentalbenefit benefitof ofsequestering sequesteringcarbon carbondioxide dioxideby bytrees. trees.

4.4. The The Exergy of of Immaterial Fluxes—Comparison Fluxes—Comparison between IEEA and EEA1, EEA2, and EEA3 4.4. 4.4. TheExergy Exergy ofImmaterial Immaterial Fluxes—Comparison between between IEEA IEEA and and EEA1, EEA1, EEA2, EEA2, and andEEA3 EEA3 With the IEEA methodology, the overall intrinsic exergy of atmospheric pollutants is much With With the the IEEA IEEA methodology, methodology, the the overall overall intrinsic intrinsic exergy exergy of of atmospheric atmospheric pollutants pollutants isis much much lower, representing on average 7% of of the environmental environmental impact measured measured by the the EEC of of emissions. lower, lower, representing representing on on average average 7% 7% of the the environmental impact impact measured by by the EEC EEC of emissions. emissions. Methane represented represented 81 to to 83% of all exergy emissions (mostly due to animal husbandry), while Methane Methane represented 81 81 to 83% 83% of of all all exergy exergy emissions emissions (mostly (mostly due due to to animal animal husbandry), husbandry), while while agriculture isisresponsible for 9898 to 99%99% of the sector’s atmospheric pollutants. The low intrinsic exergy agriculture agriculture is responsible responsible for for 98 to to 99% of of the the sector’s sector’s atmospheric atmospheric pollutants. pollutants. The The low low intrinsic intrinsic of carbon dioxidedioxide makes it negligible (Figure 14). exergy exergy of of carbon carbon dioxidemakes makesitit negligible negligible(Figure (Figure14). 14). The equivalent exergies of labour and capital in IEEA IEEA have aa lower lower share of of the exergy exergy of inputs inputs The equivalent exergies of labour and capital The equivalent exergies of labour and capitalin in IEEAhave have a lowershare share ofthe the exergyof of inputs compared with with the other EEA methodologies (Figure 15). Although the the agriculture and and forestry compared compared with the the other other EEA EEA methodologies methodologies (Figure (Figure 15). 15). Although Although the agriculture agriculture and forestry forestry subsectors need equipment, they are fixed assets and usually noncurrent assets with a long lifetime. subsectors need equipment, they are fixed assets and usually noncurrent assets with a long lifetime. subsectors need equipment, they are fixed assets and usually noncurrent assets with a long lifetime. Also, their utilization is not asasintensive as ininindustry. The need for intangible assets is also scarce for Also, Also, their their utilization utilization isis not not as intensive intensive as as in industry. industry. The The need need for for intangible intangible assets assets isis also also scarce scarce the the sector. Labour is also lessless intensive thanthan in other economic sectors, at leastleast in crop,crop, vegetables and for for thesector. sector.Labour Labourisisalso also lessintensive intensive thanin inother othereconomic economicsectors, sectors,at at leastin in crop,vegetables vegetables fruitfruit production and forestry. and and fruit production productionand andforestry. forestry.

Pollutant's Chemical Chemical Pollutant's Exergy (TJ) (TJ) Exergy

14000 14000 12000 12000

Agriculture Agriculture

Ammonia Ammonia

10000 10000 8000 8000 6000 6000 4000 4000 2000 2000 00

Methane Methane

Carbon Fisheries Carbondioxide dioxide Fisheries Forestry Forestry 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2011 2012 2012

Year Year

Figure Figure Chemical exergy Figure14. 14.Chemical Chemicalexergy exergyof ofatmospheric atmosphericpollutants pollutantsfrom fromthe theAFF AFFsector. sector.

For For agriculture agriculture and and forestry, forestry,in inEEA1, EEA1,the thesum sumof ofimmaterial immaterialfluxes fluxesisison onaverage average55 times times higher higher than than the the materials materials and and energy energyfluxes fluxes(Figure (Figure15). 15). The Themain main reason reason isis the the accounting accounting method method of of these these While the immaterial fluxes are evaluated with a cumulative approach, mass and energy flows fluxes. While the immaterial fluxes are evaluated with a cumulative approach, mass and energy fluxes. While the immaterial fluxes are evaluated with a cumulative approach, mass and energy are measured by their exergy.exergy. flows are by their flows are measured measured byintrinsic their intrinsic intrinsic exergy. EEA2, while the equivalent exergy of capital largely increased, the equivalent exergyexergy of labour In EEA2, while the equivalent exergy of largely increased, the of In EEA2, while the equivalent exergy of capital capital largely increased, the equivalent equivalent exergy of decreased. Nevertheless, both are measured with a cumulative approach and all three exergetic labour decreased. Nevertheless, both are measured with a cumulative approach and all three labour decreased. Nevertheless, both are measured with a cumulative approach and all three immaterial fluxes represent, average, on 88% of all inputs In EEA3, all 15). immaterial fluxes exergetic fluxes represent, 88% of inputs (Figure all exergetic immaterial immaterial fluxeson represent, on average, average, 88%(Figure of all all 15). inputs (Figure 15). In In EEA3, EEA3, all represent on average 86% of all inputs. immaterial fluxes represent on average 86% of all inputs. immaterial fluxes represent on average 86% of all inputs.

Input's share agriculture Input's share forfor agriculture and forestry 2012 and forestry 2012

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capital capital

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labour labour

environmental impact environmental impact

EEA2 EEA3 EEA2 EEA Methodology EEA3

IEEA IEEA

EEA Methodology

Figure 15. Input’s exergy share for agriculture and forestry (2012). Figure Figure15. 15.Input’s Input’sexergy exergyshare sharefor foragriculture agricultureand andforestry forestry(2012). (2012).

NREA, IEEA and EEA efficiencies NREA, IEEA and EEA efficiencies for agriculture and forestry for agriculture and forestry

In IEEA, material and energy fluxes represent two thirds of all inputs while the equivalent In material and energy fluxes represent two thirds of all inputs while the equivalent exergy InIEEA, material and energy fluxes exergy ofIEEA, labour represents the lowest flux. represent two thirds of all inputs while the equivalent of labour represents the lowest flux. exergy labour lowest Theofshare of represents each exergythe flux in theflux. inputs and the overall efficiency of each subsectors depends The share of each exergy flux in the inputs and thethe overall efficiency of each subsectors depends on The share of each exergy flux in the inputs and efficiency of each subsectors depends on the EEA methodology being used (Figure 16). Whileoverall in NREA the exergy of outputs is up to 2.6 the EEA methodology being used (Figure 16). While in NREA the exergy of outputs is up to 2.6 times on thehigher EEA methodology being used (Figure Whilethe in environmental NREA the exergy of outputs is up to 2.6 times than the exergy of inputs, in EEA 16). (without benefit) the output–input higher than thethan exergy of inputs, in EEA in (without the environmental benefit) the output–input relation times higher the exergy of inputs, EEA (without the environmental benefit) the output–input relation is always below 0.5. From 2000 to 2012, the efficiency increased by 36% in NREA and by isrelation alwaysisbelow 0.5. From 2000 to 2012, the efficiency increased by 36% in NREA and by 17%, 28%, always From 2000EEA3, to 2012, efficiency increased by 36% in NREA and by 17%, 28%, 33%, andbelow 32% in0.5. EEA1, EEA2, andthe IEEA, respectively (Figure 16), and by 21%, 32%, 33%, and 32% in EEA1, EEA2, EEA3, and IEEA, respectively (Figure 16), and by 21%, 32%, 37%, and 17%, 28%, 33%, and 32% in EEA1, EEA2, EEA3, and IEEA, respectively (Figure 16), and by 21%, 32%, 37%, and 32% if EB is included. 32% EB is included. 37%,ifand 32% if EB is included. 2.6 2.6 2.2 2.2 1.8 1.8 1.4 1.4 1 1 0.6 0.6 0.2 0.22000 2000

NREA NREA

EEA1* EEA1*

IEEA* IEEA* IEEA IEEA

EEA3* EEA3* EEA2* EEA2*

EEA1 EEA1 2001 2001

2002 2002

2003 2003

2004 2004

2005 2005

2006

2006 Year Year

EEA3 EEA3 2007 2008 2007 2008

2009 2009

2010 2010

EEA2 EEA2 2011 2012 2011 2012

Figure NREA, IEEA, IEEA, and and EEA EEA output–input output–input ratios ratios for for agriculture Figure 16. 16. NREA, agriculture and and forestry forestry (* (* includes includes Figure 16. NREA, IEEA, and EEA output–input ratios for agriculture and forestry (* includes Environmental Benefit). Environmental Benefit). Environmental Benefit).

For fishery subsector, subsector, the the material materialand andenergy energyinputs inputsrepresent representless lessthan than20% 20% inputs For the the fishery ofof allall inputs in For the fishery subsector, the material and energy inputs represent less than 20% of all inputs in in EEA1,2,3, while in IEEA, these fluxes represent close to 80% of all inputs (Figure 17). The fishery EEA1,2,3, while in IEEA, these fluxes represent close to 80% of all inputs (Figure 17). The fishery EEA1,2,3, is in IEEA, theseon fluxes represent close to 80% emit of allcarbon inputs dioxide (Figure Theinternal fishery subsector highly dependent fossil combustibles which in subsector iswhile highly dependent on fossil combustibles which emit carbon dioxide 17). in the the internal subsector is highly dependent on fossil combustibles which emit carbon dioxide in the internal combustion diesel engines of vessels. The EEC of removing carbon dioxide is 130 times bigger than its combustion diesel engines of vessels. The EEC of removing carbon dioxide is 130 times bigger than combustion diesel engines of vessels. The EEC of removing carbon dioxide is 130 times bigger than intrinsic exergy [21],[21], making the environmental impact flow greater than the input in EEA1, its intrinsic exergy making the environmental impact flow greater than the energy input energy in its intrinsic exergy [21], making the environmental impact flow greater than the input energy in EEA2, and EEA3 (Figure 17). EEA1, EEA2, and EEA3 (Figure 17). EEA1, EEA2, and EEA3 (Figure 17).

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Input's share for fishing Input's share for fishing 2012 2012

100%

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energy

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mass

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0%

EEA2

EEA3

IEEA

EEA Methodology EEA3 EEA2 EEA Methodology

EEA1

IEEA

Figure 17. Input’s exergy share for fishing (2012). Figure (2012). Figure17. 17.Input’s Input’sexergy exergyshare sharefor forfishing fishing (2012).

The NREA, IEEA, and EEA efficiency curves for fishing have different magnitudes and shapes. curves for different magnitudes and The The NREA and IEEA, IEEA efficiency are gradually decreasing due an increasing consumption of TheNREA, NREA, IEEA,and andEEA EEAefficiency efficiency curves forfishing fishinghave haveto different magnitudes andshapes. shapes. The NREA and IEEA efficiency are gradually decreasing due to an increasing consumption of energy energy carriers. The fish caught is regulated by European quotas and their mass and energetic The NREA and IEEA efficiency are gradually decreasing due to an increasing consumption of carriers. The fish caught is caught regulated by European andthe their mass and content content almost constant over the years. However, since energy to catch them is is energy is carriers. The fish is regulated by quotas European quotas andneeded theirenergetic mass and energetic almost constant overconstant the years. However, since the energy needed to them isto increasing, theis increasing, efficiency decreased 42% (NREA) from 2000 to catch 2012.needed Considering EEA content is the almost over thebyyears. However, since the energy catchthethem efficiency decreased by 42% (NREA) 2000 to (NREA) 2012. exergy Considering the methodologies, the methodologies, main input is, by from far,by the equivalent of the environmental impact (Figure 17). increasing, thetheefficiency decreased 42% from 2000 toEEA 2012. Considering themain EEA input is, by far, the equivalent exergy of the environmental impact (Figure 17). However, a 48% exergy However, a 48%the exergy reduction impact from 2000 to 2007 (Figure caused17). a methodologies, main input is, byin far,the theenvironmental equivalent exergy of the(EI) environmental impact reduction inaefficiency the environmental impact from 2000 to 2007 caused a doubling in efficiency the a doubling in in the same period, despite the increase in energy carriers. From 2007 caused toin2012, However, 48% exergy reduction in(EI) the environmental impact (EI) from 2000 to 2007 same in energy From 2007 toin 2012, theenergy EI stabilized the the EIperiod, stabilized and the theinincrease EEA curves begancarriers. to reflect the higher usage of carriers (Figure 18). doubling in despite efficiency the same period, despite the increase energy carriers. Fromand 2007 toEEA 2012, curves began to reflect the higher usage of energy carriers (Figure 18). A greater energy needed to Athe greater energy and needed to sustain fishery subsector, with usage the same energetic content of fish EI stabilized the EEA curvesthe began to reflect the higher of energy carriers (Figure 18). sustain the fishery subsector, the the same energetic content of the fish caught, may to indicate that caught, may indicate that fish populations are decreasing and have travel more to A greater energy needed towith sustain fishery subsector, with thevessels same energetic content offish fish populations are decreasing and the vessels have to travel more to catch the same amount. catch the may sameindicate amount.that fish populations are decreasing and the vessels have to travel more to caught, catch the same amount. NREA, IEEA and EEA NREA, IEEA and EEA efficiencies for fishing efficiencies for fishing

0.35

NREA

0.35 0.28

NREA

0.28 0.21

IEEA IEEA

0.21 0.14 0.14 0.07

EEA1,2,3

0.07 0 2000 0

EEA1,2,3 2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

Year 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Year Figure 18. NREA, IEEA, and EEA output–input ratios for the fishery sector. Figure 18. NREA, IEEA, and EEA output–input ratios for the fishery sector.

Figure 18. NREA, IEEA, and EEA output–input ratios for the fishery sector.

The IEEA efficiency is lower than NREA and higher than EEA (Figure 18). It follows the NREA The IEEA efficiency is lower than NREA and higher than EEA (Figure 18). It follows the NREA shape and gets close to it at the end of the period due to a higher share of the energetic flow. The IEEA shape The andIEEA gets close to it is at lower the end of NREA the period to than a higher of 18). the energetic The efficiency than and due higher EEAshare (Figure It follows flow. the NREA efficiency dropped 39% from 2000 to 2012. IEEA efficiency 2000 2012. shape and getsdropped close to 39% it at from the end ofto the period due to a higher share of the energetic flow. The efficiency dropped 39% from 2000 to 2012. 5.IEEA Conclusions 5. Conclusions We have reviewed past studies to identify, synthesize, and discuss the different Extended Exergy 5. Conclusions We have reviewed past studies to identify, synthesize, and discuss the different Extended Analyses (EEA) methods. In this set of studies, the estimation of the Extended Exergy Cost (EEC) of ExergyWe Analyses (EEA) methods. In thistoset of studies, the estimationdiscuss of the Extended Exergy Cost have reviewed pastdone studies identify, synthesize, thedatabase different services and products was not in a consistent way due to theand lack of a solid of Extended EEC for (EEC) of Analyses services and products wasIn not done in astudies, consistent way due toof the lack of a solid database Exergy (EEA) methods. this set of the estimation the Extended Exergy Cost inputs and the arbitrariness and double-counting associated with the methods used to quantify the of(EEC) EEC of forservices inputs and products the arbitrariness and double-counting associated withlack the methods used to done a consistent due to a solid database exergy of labour and capital. The was lack not of an EECindatabase is notway relevant forthe studiesof whose aim is the quantify the inputs exergyand of labour and capital.and Thedouble-counting lack of an EEC associated database iswith not relevant for studies of EEC for the arbitrariness the methods used to estimation of exergy efficiency of sectors and countries because, in this case, the use of an intrinsic whose aimthe is the estimation of exergycapital. efficiency oflack sectors and countries because, in this case, use quantify exergy of labour of an EEC database is not relevant forthe studies approach to estimate the exergyand of all energyThe and material input flows is the correct option. If the ofwhose an intrinsic approach to estimate theefficiency exergy ofofall energy and materialbecause, input flows is case, the correct aimwere is the estimation of exergy sectors and in this thenot use input flows valued by their EEC (cumulative exergy), thencountries the estimated efficiency would option. If the input flows were valued by their EEC (cumulative exergy), then theis estimated of an intrinsic approach to estimate the exergy of all energy and material input flows the correct characterize the specific system or economic sector, rather all that intervene to produce the output flows. efficiency not characterize specific or economic sector,exergy), rather all thatthe intervene to option. Ifwould the input flows werethe valued bysystem their EEC (cumulative then estimated produce thewould outputnot flows. efficiency characterize the specific system or economic sector, rather all that intervene to produce the output flows.

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We have classified the different approaches into 3 distinct EEA methods. The main differences are related to the methods used to estimate the equivalent exergy fluxes of labour and capital. The equivalent exergy of labour is equal to the overall input of exergy into society in EEA1 (the first EEA methodology) while in EEA2 and EEA3 (the second and third EEA methodologies), it is proportional to the population, the Human Development Index (HDI), and the per capita survival energy. The specific exergy of labour for all methodologies is the equivalent exergy of labour per working hour. The equivalent exergy of capital is the product of a monetary flow and the specific exergy of capital that is needed to convert monetary units to exergy units. In EEA1, the specific exergy of capital is the ratio of exergy input into society to a societal monetary aggregate (M2) while in EEA2 and EEA3, it is the ratio of the equivalent exergy of labour to the compensation of employees. The monetary flow is the consumption of fixed capital in EEA1, M2 in EEA2, and M2 minus compensation of employees in EEA3. In the case studies where these methodologies were applied, materials and energy flows are valued by their intrinsic exergy while, in contrast, labour and capital are valued using approaches that estimate their cumulative exergy cost. Additionally, our case study shows that results obtained for the equivalent exergy of labour and capital vary widely among these 3 methodologies, which makes the results obtained with the EEA approaches unreliable and easy to manipulate. We propose an additional method, the IEEA (Intrinsic Extended Exergy Accounting), that estimates the labour and capital inputs using an intrinsic approach, thereby contributing to the build-up of a consistent EEA methodology that can be used to estimate exergy efficiency. The IEEA is more restricted in its understanding of capital and labour fluxes than other EEA methodologies but more inclusive than the Natural Resources Exergy Accounting (NREA) methodology. It quantifies the physical and chemical exergies of the labour and capital flows consumed in the process. For labour, this is the exergy of food needed to fuel it and for capital is the estimated physical and chemical exergies of capital (machines among others) consumed in the process. The IEEA considers that for capital, the relevant monetary flux is the consumption of fixed capital (CFC) and that the intrinsic exergy of this flow is obtained assuming that the specific intrinsic exergies of intermediate consumption and capital consumed are similar. For labour, the IEEA assumes that the relevant flow is the number of hours worked and that the intrinsic exergy of this flow is the exergy of the food that is needed to maintain the workers during this time period. To account for the environmental impact (EI), the IEEA considers the intrinsic exergy of each atmospheric pollutant. In this case, it would be more consistent to consider the exergies needed to remove the pollutants from the environment or to avoid them. However, these estimations were not available in the literature. Additionally, the IEEA proposes a new category of exergy flows: the environmental benefit. For environmental benefit (EB), this methodology considers the intrinsic exergy of the carbon dioxide removed from the atmosphere. We compare the EEA methodologies (including the IEEA) using the Portuguese Agriculture, Forestry, and Fishery (AFF) sector from 2000 to 2012. For the agriculture and forestry subsectors, all methodologies estimate (1) an improvement in exergy efficiency that ranges from 17% to 37% and (2) an exergy surplus if the EB is taken into account. The NREA and IEEA methodologies also estimate an exergy surplus without the EB. The equivalent exergy of labour represented, on average, 40%, 12%, 14%, and 1% of inputs for EEA1, EEA2, EEA3, and IEEA, respectively, and 2%, 48%, 41%, and 15% for the equivalent exergy of capital. For the fishery subsector, the results are contradictory: the NREA and IEEA methodologies estimate a decrease in efficiency of 42% and 40%, respectively, while the three EEA methodologies estimate an increase in efficiency of 37%, 31%, and 34%, respectively. This contradiction is mostly explained by the environmental impact (EI). This input exergy flow, which corresponds to more than 60% of the inputs in the three EEA methodologies, has been reduced by 40% from 2000 to 2012. The equivalent exergy of labour represented, on average, 14%, 6%, 6%, and 0.2% of inputs for EEA1, EEA2, EEA3, and IEEA, respectively, while the equivalent exergy of capital represented 1%, 15%, 10%, and 15%.

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EEA is a valuable methodology; however, the lack of an EEC database and rigorous guidelines (ex. on how to correctly include capital fluxes) make it very difficult to apply the EEA without accounting for inconsistencies. The IEEA is the first attempt to move forward from a cumulative thinking into an intrinsic one, allowing correct extended efficiency metrics and providing flux accounting guidelines. The extended exergy efficiency obtained with the IEEA takes into account all the intrinsic exergies of input and output mass and energy fluxes considered with the NREA methodology plus the physical work of humans (and working animals) and the intrinsic exergy of the capital dissipated in the process. These additional flows are important to identify processes/sectors or periods of time when the dissipation of capital or human work is higher. For our case study, the IEEA extended exergy efficiency is lower than the NREA efficiency, as expected. This difference is significant for both subsectors, which means that the consumption of exergy associated with physical labour and dissipated capital is relevant but it does not have a clear trend for the time period under analysis. It is more relevant for agriculture and forestry (AF) compared to the fisheries subsector, which means that the AF subsectors are either more labour intensive and/or dissipate more capital. The IEEA methodology proposed in this paper was developed to estimate extended-exergy efficiencies. However, the IEEA approaches for labour and capital can be applied to estimate the EEC of products, avoiding double-accounting. The approach proposed for labour avoids double-counting if the food consumed to fuel working hours does not exit the system as a “useful product”. In this case, the increase in EEC of all useful products due to the labour input is compensated by a lower amount of useful products exiting the system. The same reasoning can be applied to the capital methodology; in this case, the capital goods used as production factors do not exit the system and the exergy used to produce them will increase the EEC of useful products as dissipation of capital occurs. Thus, our paper also contributes to improving the method to estimate EEC in the scope of EEA. Issues that have to be addressed in future research to promote the use of EEA results for policy and planning purposes include: the development of an EEC database and a discussion on the spatial and temporal boundaries that should be considered for different cases. Author Contributions: Conceptualization, R.M.; Data Curation, R.M.; Supervision, T.S.; Validation, T.S. and T.D.; Writing—Original Draft, R.M.; Writing—Review & Editing, T.S. and T.D. Funding: This research was funded by FCT/MCTES (PIDDAC) through project UID/EEA/50009/2013. Acknowledgments: This research was supported by European Union’s Horizon 2020 Programme—Grant Agreement no. 696231 (Project SusAn/0001/2016). We also thank the anonymous reviewers for their careful reading of our manuscript and for their insightful comments and suggestions. Conflicts of Interest: The authors declare no conflict of interest.

Abbreviations The following abbreviations are used in this manuscript: AFF CEENE CExC CFC EB EEA EEC eeK eeL EI Ein EK EL EREA

Agriculture, Forestry and Fisheries Cumulative Exergy Extraction from the Natural Environment Cumulative Exergy Consumption Consumption of Fixed Capital Environmental Benefit Extended Exergy Accounting Extended Exergy Cost Specific Exergy of Capital Specific Exergy of Labour Environmental Impact Exergy entering the society Equivalent exergy of Capital Equivalent exergy of Labour Energy Resources Exergy Accounting

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GVA HDI IC IEEA M2 NREA S

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Gross Value Added Human Development Index Intermediate Consumption Intrinsic Extended Exergy Accounting intermediate monetary aggregate Natural Resources Exergy Accounting Compensation of Employees

Appendix A. Data Sources and Values for the AFF Sector Fluxes that were directly produced and consumed inside the AFF sector were not considered and only fluxes between sectors that have economic relevance were accounted for. Although feed, incubations and seed are produced by the sector, they were considered to leave the agricultural sector to other economic activities (ex. industry and/or tertiary) and returned as an input. However green fodder, straw and manure (used as a fertilizer in crop production) that are internal outputs and inputs of activities within the sector were not accounted for. Solar radiation, vital for crop production, and water, essential for crops and livestock, were not included in the study. Sun radiation is not an anthropogenic controlled flux and it can be seen as a flux from the environment with no economic value. Water from rain follows the same thinking as it is not an anthropogenic activity but irrigation water should have been an input although the lack of trustworthy data prevented its use in the study. The food (and feed) energy content was considered equal to the metabolizable energy as defined by the USDA National Nutrient Database [49]. The energy content (combustible or gross energy) of the ingested food should be measured by a bomb calorimetry. However, foods are not fully digested and absorbed by the organism. From the ingested or gross energy, some is lost as faeces (faecal energy) and gases (combustible gas), the rest is the digestible energy. Subtracting from the digestible energy, the energy that is lost is urine and heat results in metabolizable energy [50]. Data available from the United States Department of Agriculture [49] for food energy is based on the Atwater system which is equivalent to the metabolizable energy. The choice to use the metabolizable energy was mainly due to the lack of a complete database of combustible or gross energy. Nutritional energy values assigned to each food element, in its raw state, are from USDA National Nutrient Database [49]. Moisture content of all food items was considered to be equal between USDA and Eurostat databases. Some data presented gaps in one or more years of the study. To fill in the gaps for a given resource or product, in a year or more, data was interpolated (between known values) or extrapolated (in extremes of the data set) by a linear regression made from all the other known values. Beginning with the inputs of the sector, energy carriers fluxes are available from the statistical office of the European Union, Eurostat [51] in energy units. The energy of energy carrier’s fluxes is the lower heating value (LHV) and the exergy factors for the energy carriers are the ratio of the standard chemical exergy of the organic fuels to the LHV. Table A1 presents these factors, which were obtained from Ref. [52–54]. However, the consumption matrix of energy carriers is only available in two branches, with the first being the agricultural plus the forestry subsectors and the second being the fisheries subsector. Table A1. Exergy factors for energy carriers. Energy Carrier

Factor

Energy Carrier

Factor

Energy Carrier

Factor

Biodiesels Derived Heat Electrical Energy Gas/Diesel Oil

1.11 0.6 1 1.07

Gasoline Kerosene Liquified petroleum gas (LPG) -

1.07 1.07 1.07 -

Natural gas Solid biofuels Total fuel oil -

1.04 1.107 1.07 -

Fertilizer data was downloaded from Eurostat [51], in mass units and desegregated by main nutrient or compound. The chemical exergy values (Table A2) were estimated with the corresponding

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chemical formula, multiplying molecular mass by the standard chemical exergy (values from [53] or alternatively [55]).

Fertilizer Potassium/Potash Nitrogen Phosphorus /Phosphate

Chemical Formula

Molecular Mass g/mol

Exergy kJ/mol

Exergy kJ/kg

K2 O NH4 NO3 P 2 O5

94.203 80.04348 141.9446

413.1 294.8 319.5

4385 3682 2251

Alternatively [55]

Table A2. Fertilizers’ chemical exergies. Exergy kJ/kg 4400 3680 2700

Pesticide data was also available from the Eurostat [51] in mass units and divided by function. Chemical exergy values were adopted from [55,56] being the herbicides value the average of six known herbicides and the insecticides value the average of three insecticides active substances (Table A3). Table A3. Pesticides’ chemical exergies. Pesticide Type

Exergy kJ/kg

Reference

Fungicides and bactericides

27,900

[55]

Herbicides, haulm destructors and moss killers Insecticides and acaricides Molluscicides, total Other plant protection products Plant growth regulators, total

24,100 19,900 19,900 24,100 24,100

[56]

Seeds are harvested from the crop production subsector and enter the same subsector in next sowings. This flux was included in the study since future seeds are accounted as production crops that follows a route to industry and tertiary sectors. Seeds used in agriculture are available in mass units for each plant type from the Food and Agriculture Organization of the United Nations, Faostat [57]. Specific exergy values are presented in Table A4 and available from the USDA National Nutrient Database [49,58]. Table A4. Specific Nutritional Energy (SNE) in kJ/100 g for seeds [49]. Seed

SNE

Seed

SNE

Seed

SNE

Seed

SNE

Barley Beans, dry Broad and horse beans Buckwheat Cabbages and brassicas Canary seed Castor oil seed Cereals Chick peas Cottonseed

1473 1427 1436 1381 150 1624 1800 1455 1499 1059

Cow peas, dry Grain, mixed Groundnuts Hempseed Lentils Linseed Lupins Maize Millet Mustard seed

1432 1455 1733 1800 1448 2076 1633 1527 1582 1963

Oats Oilseeds Peas, dry Poppy seed Potatoes Pulses Rapeseed Rice, paddy Rye Safflower seed

1628 1800 1448 2231 321 1423 2068 1172 1414 1314

Sesame seed Sorghum Soybeans Sunflower seed Taro (cocoyam) Triticale Vegetables, fresh Vetches Wheat Yams

2399 1377 614 1289 360 1406 150 1360 1418 422

Food given to animals is only accounted for by feed, since green plants that animals forage don’t exit the sector. Feed is available from Faostat [57] in mass units for each of the constituents. Specific exergy values were taken from Refs. [49,58] and presented in Table A5.

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Table A5. Specific Nutritional Energy (SNE) in kJ/100 g for feed components. Feed Product

SNE

Feed Product

SNE

Feed Product

SNE

Feed Product

SNE

Apples Aquatic Plants Bananas Barley Beans Butter, Ghee Cassava Cephalopods Cereals Other

218 180 371 1473 368 3001 667 343 1488

Fats, Animals, Raw Fish Body Oil Fish, Liver Oil Freshwater Fish Fruits, Other Groundnuts Maize Marine Fish Other Meat, Other

3257 3776 3776 400 203 1733 1527 400 858

1639 3700 166 2152 339 400 321 979 354

Rye Sesame seed Sesame seed Oil Sorghum Soya bean Oil Soya beans Sugar beet Sugar cane Sunflower seed

1414 2399 3700 1377 3700 614 293 135 1289

Coconuts

770

Milk

353

3700

Sweet potatoes

359

Cottonseed

1059

Millet

1582

Crustaceans Demersal Fish Eggs

300 400 682

Oats Offal, Edible Oil crops, Oil, Other

1628 486 3700

Oil crops, Other Olive Oil Onions Palm kernels Peas Pelagic Fish Potatoes Poultry Meat Pulses Rape and Mustard Oil Rape and Mustard seed Rice Roots Other -

2068

Tomatoes

74

1548 449 -

Vegetables Other Wheat -

226 1418 -

Incubating egg data is available from Eurostat [51] in number of units for each bird type. For each egg unit an average mass [59] was considered to estimate his energy. Nutritional values taken from the USDA database [49] and presented in Table A6. Table A6. Specific Nutritional Energy (SNE) in kJ/100g and average mass for eggs. Eggs

SNE

Mass (g)

Eggs

SNE

Mass (g)

Eggs

SNE

Mass (g)

Duck Eggs Geese Eggs

776 775

70 144

Guinea fowl eggs Hen eggs

663 599

9 53

Turkey eggs

716

79

As output of the AFF sector, the harvested crops include cereals, root crops, industrial crops, fibre crops, vegetables, fruits, nuts, vineyards, and olive trees. Overall nutritional energy values are obtained by multiplying each crop mass production by their specific nutritional energy. Table A7 presents all crop specific nutritional energies [49] of all products in the production database [51]. Table A7. Specific Nutritional Energy (SNE) in kJ/100 g for each harvested crop. Crop

SNE

Crop

SNE

Crop

SNE

Crop

SNE

Almonds Apples Apricots Bananas

2423 218 201 371

Mushrooms Eggplants Eggplants Endives

130 104 104 71

197 225 150 180

Radishes Raspberries Red pepper Rice

66 220 166 1548

Barley

1473

Figs

310

100

Rye and maslin

1414

Beans

368

Garlic Grain maize Hazelnuts Kiwis Leeks Lemons and acid limes Lettuces Melons Oats and mixed grain Olive trees Onions -

623

369

Sour cherries

209

117

Spinach

97

2629 255 255

Oranges Other berries Other brassicas Other citrus fruits Other fresh vegetables Other fruits Other leafy or stalked vegetables Other nuts Other pulses Peaches

2170 354 165

Strawberries Sugar beet Sunflower seed

136 293 1289

126

Pears

239

Tomatoes

74

65 141

Peas Plums

339 192

Triticale Vineyards

1406 288

1628

Pomelos and grapefruit

134

Walnuts

2738

481 166 -

Potatoes Quinces -

321 238 -

Watermelons Wheat -

127 1418 -

Black currants

264

Broad and field beans Cabbage (white) Carrots

1377 103 173

Cauliflower and broccoli

140

Celeriac Cherries

176 263

Chestnuts

891

Chicory Courgettes Cucumbers

96 80 65

1527

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Meat production is available in mass units from the Eurostat database [51] and nutritional energy values [49] were chosen as a raw mix of meat for each animal type (Table A8). Table A8. Specific Nutritional Energy (SNE) in kJ/100 g for each slaughtered meat. Meat

SNE

Meat

SNE

Meat

SNE

Meat of Bovine Animals Meat of Horses, Asses, Mules, or Hinnies

979 556

Meat of rabbits Meat of sheep and goats

569 1067

Pig meat Poultry meat

995 979

Fish catch is available by catching zones, fish families, and individually in Eurostat [51]. Table A9 presents the specific nutritional energy [49] considered for each fish, the average of their nutritional values if a family or an assumed average if in a fishing zone. The same table is used to account all energetic flux produced by aquaculture. Table A9. Specific Nutritional Energy (SNE) in kJ/100 g for fish. Fish

SNE

Fish

SNE

Fish

SNE

Abalones, winkles, conchs Aquatic mammals Carps, barbels, and cyprinids Clams, cockles, arkshells Cods, hakes, haddocks

439 462

Lobsters, spiny-rock lobsters Marine fishes not identified

469 500

Mussels Oysters

360 213

531

Miscellaneous aquatic animals

500

River eels

770

360 343

500 500

Salmon, trout, smelt Scallops, pectens

594 289

Crabs, sea-spiders

364

650

Shads

824

Flounders, halibuts, soles

294

465

Sharks, rays, chimaeras

544

Freshwater crustaceans

300

Miscellaneous coastal fishes Miscellaneous demersal fishes Miscellaneous diadromous fishes Miscellaneous freshwater fishes Miscellaneous marine crustaceans Miscellaneous marine molluscs Miscellaneous pelagic fishes

300

Shrimps, prawns

297

Herrings, sardines, anchovies King crabs, squat-lobsters

661 377

330 500

Squids, cuttlefishes, octopuses Tunas, bonitos, billfishes

343 602

Milk collection is available from the Eurostat database [51] in mass units by animal type. Specific nutritional values (Table A10) are for unprocessed milk at the producer level [49]. Table A10. Specific Nutritional Energy (SNE) in kJ/100 g for milk. Milk

SNE

Milk

SNE

Milk

SNE

Cows’ milk

268

Ewes’ milk

451

Goats’ milk

288

FAOSTAT [57] provided the produced amount of honey in mass units which has a specific nutritional energy of 1272 kJ per 100 g of product [49]. Produced eggs is available from the Faostat database [57] in mass units for hen eggs and for other birds’ eggs. Table A11 presents the specific nutritional energy of hen eggs and an average for other birds’ eggs [49]. Table A11. Specific Nutritional Energy (SNE) in kJ/100 g for eggs. Eggs

SNE

Eggs

SNE

Hen eggs

599

Other bird’s eggs

776

Wood removals are available from the Eurostat database [51] in volume units considered as under bark with a moisture content of 20%. Specific exergy values (Table A12) obtained from Dewulf et al. [38] with densities of 450 kg/m3 for softwoods and 650 kg/m3 for hardwoods.

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Table A12. Wood exergies per type of wood [38]. Wood

Exergy (MJ/kg)

Exergy (GJ/m3 )

Wood

Exergy (MJ/kg)

Exergy (GJ/m3 )

Coniferous

17.688

7.9596

Non-coniferous

17.608

11.4452

Animal skins production data [57] (including wool) is only available for goats and sheep but the absence of a specific exergetic value for skins lead us to consider only the wool production flux that has a specific exergy of 5850 kJ/kg [12]. Environmental remediation exergy costs were estimated by multiplying the pollutant air emission (obtained in mass units from Eurostat [51]) by the specific extended cost of removing the pollutant from the atmosphere. Seckin et al. [21] created a virtual process to find the environmental extended exergy cost of carbon dioxide, methane and nitrous oxide while Dai et al. [20] determined the specific environmental remediation exergy cost of carbon monoxide, nitrogen oxides and sulphur oxides. For ammonia, the chemical exergy [53] was used as the extended exergy cost of removing the pollutant since no study is available in the literature (Table A13). Table A13. Specific environment remediation exergy cost (SEEC) and chemical exergy (Ex,ch) in kJ/kg for each atmospheric pollutant. Pollutant

SEEC

Ex,ch

Pollutant

Ammonia Carbon dioxide Carbon monoxide

19,841 57,600 11,800

19,841 442.6 9825

methane nitrogen oxides -

SEEC 322,400 3610 -

Ex,ch

Pollutant

SEEC

Ex,ch

51,810.7 2963 -

nitrous oxide sulphur oxides -

10,600 5890 -

2430 4892 -

Labour data [51] is available in number of workers per AFF subsector as well as all country population (Table A14). Table A14. Population and workers allocated to each AFF subsector (thousands). 2012 Population Agriculture Forestry Fishery

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

10,514 10,557 10,573 10,568 10,558 10,542 10,522 10,503 10,483 10,458 10,419 10,362 10,289 497.2 489.8 508.8 534.3 542.2 546.2 556.9 557.3 566.7 591 585.9 604.3 584.6 10.9 10.9 10.6 10.7 12.0 11.8 11.8 11.7 11.7 11.8 11.7 11.9 11.6 14.0 14.3 14.0 13.9 14.4 14.3 15.0 14.9 15.0 15.0 14.8 15.0 14.8

All economic values such as compensation for employees, agricultural gross value added (GVA), monetary aggregate M2, and gross domestic product (GDP) [51] (Table A15) were obtained at current prices and converted to constant euro GDP prices through a GDP price deflator obtained from the economic and financial affairs of the European commission (Ameco) [60] (Table A16). The GDP price deflator is referenced to 2010 and measures the ratio between real GDP and the nominal GDP, providing a measure of inflation over the period. Table A15. Monetary values of all sectors and AFF sector at constant 2010 prices (Billion Euro for Total values and Million Euro for subsectorial values). Total—All sectors, GVA—gross value added, Wages—Compensation of employees. 2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

Total GVA Total M2

141 163

149 174

151 173

149 170

151 179

151 163

147 159

146 157

148 150

145 147

147 147

147 153

145 151

Agriculture GVA Agriculture M2 Agriculture Wages

2224 2585 817

2184 2537 756

2413 2765 787

2440 2776 784

2497 2946 782

2538 2735 787

2887 3113 778

2891 3097 795

3272 3312 780

3260 3294 775

3337 3327 768

3655 3784 825

3869 4019 823

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Table A15. Cont.

Forestry GVA Forestry M2 Forestry Wages Fishery GVA Fishery M2 Fishery Wages

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

647 752 108 399 464 170

689 800 104 412 478 160

657 753 102 396 454 156

613 697 98 378 430 160

662 782 105 419 494 175

682 735 101 418 450 178

708 763 100 413 445 176

716 767 102 416 446 179

785 795 100 459 464 176

814 822 100 459 464 175

893 890 99 476 474 173

893 924 106 509 527 186

841 874 106 521 541 186

Table A16. Price deflator values referenced to 2010. 2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

99.333

99.730

100

99.360

98.283

96.604

93.809

90.913

87.984

85.925

83.068

79.714

76.859

The Human Development Index (HDI) for Portugal is presented on Table A17. Table A17. HDI values for Portugal. 2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

0.827

0.824

0.818

0.812

0.809

0.804

0.797

0.793

0.79

0.792

0.789 0.788

0.782

Appendix B. Exergy Input to Society In EEA1, the equivalent exergy of labour and capital is equal to the total amount of exergy that enters the region in a given year. To measure the overall input exergy, referred as domestic consumption, we will account all primary products that are internally processed. Domestic consumption is the domestic production plus imports less exports. The primary products considered are the outputs from agriculture (cereals, roots, sugar crops, pulses, nuts, oil crops, vegetables, fruits, fibers, fodder crops, and grazed biomass), the output from the fishery (fish catch) and forestry (wood) subsectors, the output from the extraction sector, including minerals (marble, granite, sandstone, chalk and dolomite, slate, salt, limestone and gypsum, clays and kaolin, sand and gravel) and metal ores (iron, copper, zinc and bauxite and other aluminium). Animal husbandry outputs were not included because the exergy to feed the cattle was already taken into account as fodder crops or grazed biomass. The total exergy of energy carriers was also accounted for (solid fuels, petroleum products, gas, renewable energies, and electrical energy). Data from the extraction sector as well as trades with other countries were downloaded from the Eurostat database [51] in mass units. All specific exergy values for minerals and metal ores were obtained from Ref. [12] and present in Table A18. Table A18. Specific Exergy values for minerals and metal ores. Mineral

Exergy kJ/kg

Metal Ore

Exergy kJ/kg

Marble, granite, sandstone Chalk and dolomite Slate Salt Limestone and gypsum Clays and kaolin Sand and gravel

820.96 81.88 131.49 244.7 49.95 697.99 131.49

Iron Copper Zinc Bauxite and other aluminium -

79.77 523.09 1237.83 1114.16 -

Exergy factors presented in Table A19 which are the ratio of the standard chemical exergy of the organic fuels (or energy carrier in electrical and heat flows) to the LHV were retrieved from Ref. [52–54]. The sum of all exergy of primary products consumed in the country is calculated by the product of each flux by the specific exergy or exergy factor. The sum of all exergetic fluxes is presented in Figure A1.

Table A19. Exergy factors for energy carriers. Energy Carrier

Factor

Energies 2018, 11, 2522 Biodiesels

Biogas Biogasoline Bituminous coal Charcoal

Energy Carrier

Coke oven coke

Energy Carrier

Factor

Energy Carrier

Factor

1.11 Electrical energy 1 Natural gas 1.04 Gas works gas 1 Petroleum products 1.11 Geothermal energy 0.6 Solar photovoltaic Table A19. Hydro Exergypower factors for energy 1.06 1 carriers. Solar thermal 1.11 Industrial wastes 1.1 Solid biofuels Factor Energy Carrier Factor Energy WasteCarrier 1.05 Liquid biofuels 1.11 1.11 Electrical energy 1 Natural gas (non-renewable) 1.04 Gas works waste gas 1 Petroleum products 1.06 Municipal 1.1 Wind power

1.04 28 of 32 1.07 1 0.25 1.107 Factor

1.1

Biodiesels 1.04 Biogas coal Coking 11.07 Biogasoline 1.11 Geothermal energy 0.6 Solar photovoltaic 1 Bituminous coal 1.06 Hydro power 1 Solar thermal 0.25 The sum of all exergy1.11 of primaryIndustrial products consumed in1.1 the countrySolid is calculated product Charcoal wastes biofuels by the 1.107 (non-renewable) 1.1 Cokeflux ovenby coke 1.05 biofuels 1.11 of allWaste of each the specific exergy orLiquid exergy factor. The sum exergetic fluxes is presented in 1.06 Municipal waste 1.1 Wind power 1 FigureCoking A1. coal

Electrical energy

1400000

Renewable energies

Exergy (TJ)

1050000

Gas

700000

Petroleum products

350000 Minerals Agriculture

Wood 0 2000

2001

2002

2003

2004

2005

2006

Year

Solid fuels

2007

2008

2009

2010

2011

2012

Figure A1. Exergy ofofprimary (fisheriesand andmetals metalsare arebarely barelyvisible). visible). Figure A1. Exergy primaryfluxes fluxesconsumed consumed by by society society (fisheries

Overall, thetheexergy from 2000 2000 toto2012 2012mainly mainlydue duetoto a 66% Overall, exergyconsumption consumption decreased decreased by 11% 11% from a 66% reduction in petroleum products in the same period from 51% of all inputs in 2000 to 38% in 2012. reduction in petroleum products in the same period from 51% of all inputs in 2000 to 38% in 2012. Food from agriculture and fisheries represented 8.4% in 2012, little less thanless wood which represented Food from agriculture and fisheries represented 8.4% ina 2012, a little than wood which represented 8.8% of combined all inputs. The combined domesticof consumption of metalsis and minerals is below 8.8% of all inputs. The domestic consumption metals and minerals below 2%. The energy 2%. The energy flows used for energy conversion represented 83% of all exergy consumption in 2000 flows used for energy conversion represented 83% of all exergy consumption in 2000 and 81% in 2012. and 81%energies in 2012. and Renewable and gas their have share, been increasing their share, while petroleum Renewable gas haveenergies been increasing while petroleum products and solid fuels andMetal solidand fuels are Metal and fishexergetic are barely visible since exergetic areproducts decreasing. fish aredecreasing. barely visible since their contributions aretheir too low. contributions are too low. Figure A2 shows the ratio between the domestic production to consumption for each primary Figure is A2completely shows the dependent ratio between the domestic production consumption forfrom eachthe primary flux. Portugal on fossil fuels because it doestonot extract them natural flux. Portugal is completely dependent on fossil fuels because it does not extract them from the environment. In contrast, for wood, minerals, metals, vegetables, nuts, fodder crops, and eventually natural environment. In contrast, for wood, minerals, metals, vegetables, nuts, fodder crops, and fruits, production is higher than consumption. The country is dependent on fish, roots, pulses, and cereals eventually fruits, production is higher than consumption. The country is dependent on fish, roots, and imports almost all of its consumption of oil crops, fibers, and lately sugar crops. The total ratio of pulses, and cereals and imports almost all of its consumption of oil crops, fibers, and lately sugar domestic production vs. consumption (including energy carriers) slightly increased from 25% in 2000 to crops. The total ratio of domestic production vs. consumption (including energy carriers) slightly Energies 2018,which 11, x FOR PEER REVIEW 29 of 33 30% in 2012 is explained by a 11% decrease in consumption and a 4% increase in production. increased from 25% in 2000 to 30% in 2012 which is explained by a 11% decrease in consumption and a 4% increase in production. Domestic production / Domestic consumption

1.2

Wood

Minerals

1

Metals

Vegetables

Fodder crops

Nuts

0.8

Fruits Fish

0.6 0.4

Roots

Sugar crops Pulses

0.2

Cereals

Total Oil crops

Fibers

0 2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

Year Figure vs.domestic domesticconsumption consumption society. FigureA2. A2.Exergy Exergyratio ratioof ofdomestic domestic production production vs. byby allall society.

Appendix C. NREA and EEA Efficiencies of Previous Studies Table A20 synthesizes the equivalent exergy of capital input–output relations plus NREA versus EEA Efficiency for the several economic sectors obtained by the referenced studies.

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Appendix C. NREA and EEA Efficiencies of Previous Studies Table A20 synthesizes the equivalent exergy of capital input–output relations plus NREA versus EEA Efficiency for the several economic sectors obtained by the referenced studies. Table A20. Comparison of exergetic input and output capital fluxes (Ek ) and Efficiency (NREA exergy Efficiency—εNREA vs. EEA Efficiency—εEEA ) of societal studies. Study [10] [22] [23] [11] [24] [25]

Agriculture

Extraction

Conversion

Industry

Transport

Tertiary

Domestic

Ek,in > Ek,out εNREA < εEEA Ek,in < Ek,out εNREA > εEEA Ek,in > Ek,out εNREA > εEEA Ek,in > Ek,out εNREA > εEEA Ek,in > Ek,out εNREA < εEEA Ek,in < Ek,out εNREA < εEEA

Ek,in > Ek,out εNREA > εEEA Ek,in > Ek,out εNREA = εEEA Ek,in > Ek,out εNREA > εEEA Ek,in > Ek,out εNREA > εEEA Ek,in > Ek,out εNREA > εEEA Ek,in < Ek,out εNREA < εEEA ≈1

Ek,in > Ek,out εNREA < εEEA Ek,in > Ek,out εNREA > εEEA Ek,in > Ek,out εNREA > εEEA Ek,in < Ek,out εNREA < εEEA Ek,in > Ek,out εNREA < εEEA Ek,in = Ek,out εNREA < εEEA

Ek,in > Ek,out εNREA < εEEA Ek,in < Ek,out εNREA < εEEA Ek,in < Ek,out εNREA < εEEA Ek,in < Ek,out εNREA < εEEA Ek,in > Ek,out εNREA < εEEA

Ek,in > Ek,out εNREA < εEEA Ek,in > Ek,out εNREA < εEEA Ek,in < Ek,out εNREA < εEEA Ek,in < Ek,out εNREA < εEEA Ek,in > Ek,out εNREA < εEEA Ek,in < Ek,out εNREA < εEEA

Ek,in > Ek,out εNREA < εEEA Ek,in < Ek,out εNREA > εEEA Ek,in > Ek,out εNREA < εEEA Ek,in < Ek,out εNREA < εEEA Ek,in >Ek,out εNREA < εEEA Ek,in < Ek,out εNREA < εEEA

Ek,in > Ek,out εNREA < 1 < εEEA Ek,in = Ek,out = 0 0 = εNREA Ek,out 0 = εNREA Ek,out = 0 εNREA Ek,out = 0 εNREA < 1 < εEEA

Ek,out

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